Chemistry — MPSC PYQ

कार्बन डायऑक्साइड आणि कार्बोनेट्स् कोणत्या प्रकारची संयुगे आहेत ? / Carbon dioxide and carbonates are which types of compounds ?

Carbon dioxide and carbonates are classified as inorganic compounds despite containing carbon, because they do not possess carbon-hydrogen (C-H) bonds typical of organic molecules.

खालीलपैकी कोणते विधान ग्रॅफाइट बाबत सत्य आहे ? Which of the following statements is true about graphite ?

Graphite is an allotrope of carbon that is soft, slippery, and an excellent conductor of electricity due to the presence of free electrons.

कार्बनचा अणुक्रमांक किती आहे ? What is the atomic number of carbon ?

Carbon is a chemical element with the symbol C and atomic number 6, meaning it has 6 protons in its nucleus.

खालीलपैकी कोणते कार्बनचे अपरूप (allotrope) नाही ? Which of the following is not an allotrope of carbon ?

Allotropes are different forms of the same element. Graphite, diamond and fullerene are all pure carbon, while carbon dioxide is a compound of carbon and oxygen, so it is not an allotrope.

खालीलपैकी कोणत्या गुणधर्मामुळे कार्बन अनेक संयुगे तयार करू शकतो ? Which of the following properties makes carbon capable of forming many compounds ?

Carbon forms a massive number of compounds due to its tetravalency (valency of 4) and catenation (the unique ability to form long chains with other carbon atoms).

मॅग्नेशियम क्लोराइड ह्या संयुगाची निर्मिती करताना मॅग्नेशियम व क्लोरीनच्या अणूंमध्ये कोणता रासायनिक बंध तयार होतो ? / Which chemical bond is formed between Mg and Cl atoms during formation of compound MgCl2?

Magnesium is a metal with 2 valence electrons that it donates, and Chlorine is a non-metal that accepts electrons, forming an ionic bond (electrovalent bond) through complete transfer of electrons.

व्यावसायिक तंतूंच्या उत्पादनात लकरीला पर्याय म्हणून खालीलपैकी कोणाचा वापर केला जातो ? / Which of the following is used as a substitute for wool in the production of commercial fibers?

Polyacrylonitrile (PAN) is a synthetic polymer used as a substitute for wool in the production of commercial synthetic fibers like Orlon or acrylic.

खालीलपैकी कोणत्या औषधाचे वर्गीकरण वेदनाशामक आणि ज्वरशामक असे केले जाऊ शकते ? / Which of the following medicine can be classified as both Analgesics and Antipyretics?

Paracetamol acts both as an analgesic (relieves pain) and an antipyretic (reduces fever), making it a dual-purpose medicine.

हायड्रोजनचे समस्थानिके आणि त्यांचे अनुक्रमे वस्तुमान गुणोत्तर ________ आहे. The isotopes of hydrogen and their respective mass ratio are ________.

The isotopes of hydrogen are Protium, Deuterium, and Tritium, with mass numbers 1, 2, and 3 respectively, giving a mass ratio of 1 : 2 : 3.

खालील विधाने विचारत घ्या. रासायनिक अभिक्रियेचा दर हा ______ वरीलपैकी कोणते विधान/विधाने बरोबर आहेत ? / Consider the following statements : Rate of a chemical reaction is _______ Which of the statement given above is/are correct ?

The rate of a chemical reaction is directly proportional to the concentration of reactants (higher concentration means more collisions) and increases with an increase in temperature (higher kinetic energy).

रासायनिक खतांच्या अतिवापरामुळे शेतजमिनीतील वाढलेल्या अम्लाचे उदासिनीकरण करण्यासाठी कोणते रसायन वापरतात ? / Which chemical compound is used to neutralize the acidity of soil increased due to excessive use of Chemical Fertilizers ?

Lime water (calcium hydroxide) or agricultural lime is basic in nature and is used to neutralize the excess acidity in soil caused by overuse of chemical fertilizers.

खालीलपैकी कोणती/त्या धातुंची/च्या जोडी/जोड्या त्यांच्या खनिजांपासून वेगळे करण्यासाठी साईनाईड जटिल आयनचे द्रावण वापरतात ? / Which of the following pair/pairs of metal/metals can be extracted from their ores by using cyanide complex solutions ?

Cyanide process (MacArthur-Forrest cyanide process) is a hydrometallurgical technique used for extracting precious metals like Gold (Au) and Silver (Ag) from their ores.

खालील रासायनिक अभिक्रिया कोणत्या प्रकारात मोडते ते ओळखा ? 2KClO3(s) --[Δ]--> 2KCl(s) + 3O₂ ↑ Identify the type of following chemical reaction. 2KClO3(s) --[Δ]--> 2KCl(s) + 3O₂ ↑

When potassium chlorate (2KClO₃) is heated (Δ), it breaks down into potassium chloride and oxygen gas. This is a classic example of a thermal decomposition reaction.

खालीलपैकी कोणत्या समस्थानिकाला जड हायड्रोजन असे म्हणतात ? From the following which isotope is called as heavy hydrogen ?

Deuterium (²H or D), an isotope of hydrogen containing one proton and one neutron, is commonly known as heavy hydrogen and is used to produce heavy water (D₂O).

__________ हे तेल आणि चरबीमधले असंतृप्तता मोजण्यासाठी वापरतात. __________ is used to estimate the presence of unsaturation in oils and fats.

Iodine value is the mass of iodine in grams that is consumed by 100 grams of a chemical substance (like oils or fats), used to measure the degree of unsaturation (double bonds).

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संयुग H-C(CH₃)-C(OH)-OH म्हणजेच C₃(H₂O)₃ हे / The compound H-C(CH₃)-C(OH)-OH i.e. C₃(H₂O)₃ is

The given compound H-C(CH₃)-C(OH)-OH does not fit the standard definition of a carbohydrate (polyhydroxy aldehydes or ketones with multiple hydroxyl groups on different carbons).

संयुग 'A' चे जलीय अपघटन (तीन H₂O वापरून) योग्य परिस्थितीत केले असता एक ग्लुकोज एकक, एक फ्रुक्टोज एकक आणि दोन गॅलॅक्टोज एकक तयार होतात, तर 'A' चे रेणुसुत्र ____________ हे आहे. / The compound 'A' undergoes hydrolysis (Using three H₂O) under appropriate conditions to form a unit of glucose, a unit of fructose and two units of galactose. The molecular formula of the compound 'A' is

Compound A is a tetrasaccharide formed by 1 glucose (C6H12O6), 1 fructose (C6H12O6), and 2 galactoses (C6H12O6). Total formula before hydrolysis: 4 monosaccharide units = 4*(C6H12O6) = C24H48O24. Subtracting 3 H2O molecules (H6O3) yields C24H42O21.

(HO-C-H)_3 हे संयुक ____________ आहे आणि ह्यात प्रतिबिंबिरूपितांच्या ____________ जोड्या आहेत. / The compound (HO-C-H)_3 is a ____________ and has ____________ pairs of optical isomers.

The condensed formula represents a ketohexose (6 carbons with a keto group). Based on stereochemistry, a ketohexose with 3 asymmetric centers has 4 pairs of optical isomers (enantiomers).

खालीलपैकी कोणता पर्याय संयुगे 'A' आणि 'B' च्या बाबतीत अचूक आहे ? A = CH2OH-C(=O)-(HO-C-H)_3-CH2OH, B = H-C(=O)-(HO-C-H)_4-CH2OH / Which of the following option is correct about compounds A and B ? A = CH2OH-C(=O)-(HO-C-H)_3-CH2OH, B = H-C(=O)-(HO-C-H)_4-CH2OH

Compound A is a ketohexose (contains a ketone group) and Compound B is an aldohexose (contains an aldehyde group). Since they have the same molecular formula but different functional groups, they are functional isomers.

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खालीलपैकी कोणती संयुगे प्रकाशीीय क्रियाशीलता दाखवतील ? / Which of the following compounds will show optical activity ?

Optical activity requires the presence of chiral carbon atoms (asymmetric carbons bonded to four different groups). Compounds A and C possess chiral centers, hence they show optical activity.

0.10M जलिय HCl द्रावणाचा pH काढण्यासाठी खालीलपैकी कोणता गणितीय संबंध वापरावा ? Which of the following mathematical relationships should be used to calculate the pH of a 0.10M aqueous HCl solution ?

pH is defined as the negative logarithm of hydrogen ion concentration: pH = -log10[H+]. For 0.10M HCl, [H+] = 0.10 or 1.0 x 10⁻¹ M, giving pH = -log10(1.0 x 10⁻¹).

1.5M H₂SO₄ च्या 10 dm³ द्रावणापासून 1.0N H₂SO₄ चे द्रावण कसे बनवाल ? How is 1.0N H₂SO₄ solution is prepared from 10 dm³ of 1.5M H₂SO₄ solution ?

Normality (N) = Molarity (M) x n-factor. For H2SO4, n-factor is 2, so 1.5M H2SO4 is 3.0N. Using dilution formula N1V1 = N2V2 (3.0 x 10 = 1.0 x V2), the final volume V2 must be 30 dm³. Since we already have 10 dm³, we need to add 20 dm³ of water.

NH₃ आणि BF₃ च्या आकारांबद्दल खालीलपैकी कोणता पर्याय अचूक आहे ? Which of the following is correct for the shapes of NH₃ and BF₃ ?

NH3 has 3 bond pairs and 1 lone pair, resulting in a pyramidal shape due to sp3 hybridization and lone pair-bond pair repulsion. BF3 has 3 bond pairs and no lone pairs, resulting in a trigonal planar shape due to sp2 hybridization.

खालीलपैकी कोणत्या हायड्रोकार्बनमध्ये 80% कार्बन असतो ? (H = 1, C = 12) Which of the following hydrocarbon has 80% carbon ? (H = 1, C = 12)

Percentage composition by mass = (mass of carbon / molar mass) x 100. Ethane (C2H6): molar mass = 2(12) + 6(1) = 30. %C = 24/30 x 100 = 80%. For comparison: Methane (CH4) is 75% C, Benzene (C6H6) is 92.3% C, Cyclohexane (C6H12) is 85.7% C -- only Ethane matches the given 80%.

180 ग्रॅम अॅसेटिक आम्ल (CH3COOH) आणि 180 ग्रॅम पाणी (H2O) एकमेकांत मिसळले. तयार झालेल्या द्रावणात अॅसेटिक आम्लाचा मोल फॅक्शन ______ इतका असेल. [H = 1, C = 12, O = 16] 180 g of acetic acid (CH3COOH) is mixed with 180 g of water (H2O). The mole fraction of acetic acid in the resultant solution is [H = 1, C = 12, O = 16]

Molar mass of CH3COOH = 12+3+12+16+16+1 = 60 g/mol. Moles of CH3COOH = 180 / 60 = 3. Molar mass of H2O = 18 g/mol. Moles of H2O = 180 / 18 = 10. Mole fraction of acetic acid = Moles of acid / Total moles = 3 / (3 + 10) = 3 / 13 = 0.23.

जर 1.0 मोल आदर्श वायूचे आकारमान मानक तापमान आणि दाबाला 22.4 Lit असेल तर सर्वकष वायु स्थिरांक, R ______ असतो. If one mole of an ideal gas occupies 22.4 Lit at Standard Temperature and Pressure, then the value of the universal gas constant R is

The universal gas constant R = 0.0821 atm.L.mol-1.K-1, equivalently 8.314 J.K-1.mol-1 or 8.314x10^7 erg.K-1.mol-1 (since 1 J = 10^7 erg). Option (a) states this correctly in atm.L units. Option (b) is wrong because it labels the value Joules, not erg -- 8.314x10^7 is only correct when the unit is erg. Option (d) gives the right unit (erg) but drops the x10^7 factor.

हिऱ्यामध्ये कार्बनचा एक अणू हा कार्बनच्या इतर अणूंनी ______ रचनेने घेरेलेला असतो. In a diamond, each carbon atom is ______ surrounded by other carbon atoms.

In diamond, each carbon atom undergoes sp3 hybridization and is covalently bonded to four other carbon atoms in a tetrahedral arrangement.

ट्रीटियमचा अणुक्रमांक ______ आहे. An atomic number of Tritium is ______

Tritium is an isotope of hydrogen. All isotopes of an element share the same atomic number, which is 1 for hydrogen (Protium, Deuterium, and Tritium all have atomic number 1).

दिलेल्या संयुजा कक्षेतील इलेक्ट्रॉनच्या जोड्यांमधील – उदा. विमुक्त जोडी – विमुक्त जोडी (वि.जो. – वि.जो.); बंधित जोडी – बंधित जोडी (बं.जो. – बं.जो.) व विमुक्त जोडी – बंधित जोडी (वि.जो. – बं.जो.) विद्युतस्थितिक प्रतिकर्षंन _______ असे कमी होत जाते. The electrostatic repulsion between electron pairs such as lone pair – lone pair (l.p. – l.p.), bond pair – bond pair (b.p. – b.p.) and lone pair – bond pair (l.p. – b.p.) in a given valence shell decreases in the order of _______

According to VSEPR theory, electrostatic repulsion between electron pairs follows the order: lone pair - lone pair (lp-lp) > lone pair - bond pair (lp-bp) > bond pair - bond pair (bp-bp).

यामध्ये सगळयात जास्त रेणू असतील. [H = 1, C = 12, O = 16, I = 127] The maximum number of molecules are present in _______ [H = 1, C = 12, O = 16, I = 127]

To find the maximum number of molecules, calculate the number of moles for each given option by dividing the given mass by its molar mass, then multiply by Avogadro's number. The substance with the highest moles will have the maximum molecules.

V2O7⁴⁻ मध्ये V ची ऑक्सिडीकरण स्थिती ही ______ आहे. The oxidation state of V in V2O7⁴⁻ is _______

In V2O7⁴⁻, let the oxidation state of V be x. Therefore, 2(x) + 7(-2) = -4, which gives 2x - 14 = -4, so 2x = +10, and x = +5.

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7 ग्रॅम वायुरूप नायट्रोजनचे N₂, 2 atm दाबान आणि 546 K तापमानात _______ dm³ इतके घनफळ असते. 7 g of gaseous nitrogen N₂ occupies _______ dm³ at 546 K and 2 atm.

Using the Ideal Gas Law (PV = nRT), moles of N2 (n = 7/28 = 0.25 mol), P = 2 atm, T = 546 K, R = 0.0821. Solving gives V = 5.6 dm³.

समुद्रपातळीवर असलेल्या प्रयोगशाळेत वापरण्यासाठी, वर्षाच्या कोणत्याही दिवशी खालीलपैकी सगळ्यात योग्य संहति एकक/एकके _________ हे/ही आहे/आहेत. On any day of the year, to use in laboratories at sea level the most correct concentration unit/s is/are _________.

Molality is independent of temperature because it is expressed in terms of mass of solvent (kg), whereas molarity and normality depend on volume which varies with temperature.

जेव्हा 4.9 ग्रॅम H₂SO₄ हे V घनसेिंटीमीटर द्रावणत असते, तेव्हा त्या द्रावणची प्रसामान्यता 0.025 N इतकी असते, तर V = _________ 4.9 g of H₂SO₄ is present in V cm³ 0.025 N solution of sulphuric acid, then V = _________

Normality = (Weight / Equivalent weight) × (1000 / V in mL). For H2SO4, equivalent weight = 49. Given Normality = 0.025, W = 4.9 g, solving gives V = 4000 cm³.

10 ग्रॅम वायुरूप हायड्रोजनमध्ये H₂, मानक दाब आणि तापमानात हायड्रोजनचे _________ मोल असतात. 10 g of gaseous hydrogen H₂, at NTP/STP contain _________ mol of hydrogen.

Number of moles is calculated as given mass divided by molar mass. Molar mass of H2 is 2 g/mol. So, 10 g / 2 g/mol = 5 moles.

एका अनुमापनी विश्लेषणणात, 25 घनसेिंटीमीटर 0.1 N नायट्रिकआम्ल _________ घनसेिंटीमीटर 0.25 N पोटॅशिअम हायड्रॉक्साइड पूर्णपणे अभिक्रिया करेल. In a titrimetric analysis, 25 cm³ of 0.1 N HNO₃ would react completely with _________ cm³ of 0.25 N KOH.

Using the neutralization formula N1V1 = N2V2: (0.1 N) * (25 cm³) = (0.25 N) * V2. Solving for V2 gives (2.5 / 0.25) = 10 cm³.

खालील विधानें पहा : / Consider the following statements :

An atom is electrically neutral because the positive charge on its nucleus equals the total negative charge of all orbiting electrons, making statement (a) correct and statement (b) incorrect since the nuclear charge is positive, not negative.

कॅल्शियम ऑक्साईड (CaO) ची स्टेबल् ऑक्टेट मिळविण्यासाठी : In CaO, so as to achieve the stable octate:

Calcium transfers its 2 valence electrons to Oxygen, forming an ionic bond where Calcium achieves a stable octet configuration (noble gas structure).

32 ग्रॅम मिथेन (रेणु वस्तुमान 16 g/mol) आणि 192 ग्रॅम ऑक्सिजन (रेणु वस्तुमान 32 g/mol) एकत्र मिसळले. हे दोन वायू जर एकमेकांशी रासायनिक प्रक्रिया करत नसतील तर मिथेन वायूचे मोल फ्रॅक्शन किती ? / 32 g of methane (molar mass 16 g/mol) is mixed with 192 g of oxygen (molar mass 32 g/mol). Presuming that these gases donot react with each other, what is the mole fraction of methane ?

Moles of methane = 32/16 = 2 moles. Moles of oxygen = 192/32 = 6 moles. Total moles = 2 + 6 = 8 moles. Mole fraction of methane = Moles of methane / Total moles = 2/8 = 0.25 (or 1/4).

खालील दिलेल्या विधानापैकी कोणती विधाने बरोबर आहेत ? / Which of the following statements are correct ?

Diamond is a non-conductor of electricity and is used in rock drilling; graphite has a two-dimensional sheet-like structure and is a good electrical conductor.

कोणाची आयनन ऊर्जा (IE) सर्वात जास्त आहे ? / Which has maximum Ionization Energy ?

Ionization energy increases across a period and decreases down a group. Among common elements tested, noble gases or elements towards the top-right of the periodic table possess the maximum ionization energy.

रासायनिक अभिक्रियेचा वेग हा साधारणपणे _____ Chemical reaction rates generally _____

The rate of a chemical reaction is highest at the beginning because reactant concentrations are at their maximum, and it decreases over time as reactants are consumed.

_____ हा सौम्य क्षपणक आहे, जो फक्त कार्बोनील गटाचे क्षपण इतर गट उदा. नायट्रो, कार्बोक्झिल, इस्टर, दुहेरी बंध असताना करतो. The mildest reducing agent which reduces only carbonyl group in presence of nitro, carboxyl, double bond and ester group is _____

Sodium borohydride (NaBH4) is a mild reducing agent that selectively reduces carbonyl groups (aldehydes and ketones) without affecting other functional groups like nitro, carboxyl, double bonds, or esters.

खालील विधानांचा विचार करा : Consider the following statements :

In dead plants or animals, radioactive Carbon-14 decays while stable Carbon-12 remains constant, causing the C-14 to C-12 ratio to change over time (statement a). This changing ratio is precisely why Carbon-14 isotope is used in carbon dating to determine the age of fossils (statement b). Thus, (a) is true and explains (b).

खालीलपैकी कोणत्या रासायनिक अभिक्रिया ऑक्सिडिकरण-क्षपण या प्रकारात मोडतात ? (a) 2Mg + O2 → 2MgO (b) MnO2 + 4HCl → MnCl2 + 2H2O + Cl2 (c) 2Na + Cl2 → 2NaCl (d) 2NaBr + H2O2 → 2NaOH + Br2 Which of the following are Oxidation-reduction reactions ? (a) 2Mg + O2 → 2MgO (b) MnO2 + 4HCl → MnCl2 + 2H2O + Cl2 (c) 2Na + Cl2 → 2NaCl (d) 2NaBr + H2O2 → 2NaOH + Br2

All given chemical reactions involve simultaneous oxidation and reduction (redox reactions) where electrons or oxygen/hydrogen are transferred.

रासायनिक घटाचे विद्युतगामक बल धन असते, जेव्हा अभिक्रियेचा मुक्त ऊर्जा बदल हा असतो. The EMF of a chemical cell is positive, when the free energy change of the reaction is .

The relationship between cell emf (E) and Gibbs free energy change (delta G) is given by delta G = -nFE. For the EMF to be positive (>0), the free energy change must be negative (<0) for a spontaneous process.

आधुनिक आवर्तसारणीतील अणूची त्रिज्या हा आवर्ती गुणधर्म विचारात घेता खालीलपैकी कोणती विधाने बरोबर आहेत ? / In modern periodic table, which of the following statements about atomic radius are true ?

Atomic radius increases down a group due to the addition of new electronic shells, and decreases across a period from left to right due to increased effective nuclear charge.

खालीलपैकी कोणास टरपिनॉइड समजले जातात ? / Which of the following is/are terpenoid/s ?

Terpenoids are a large class of naturally occurring organic compounds derived from five-carbon isoprene units. Both menthol (a monoterpene) and Vitamin A (a diterpenoid) belong to this class.

टेट्राहेड्रल [Ni(CO)4] व्यामिश्र/जटिल (complex) मध्ये विजोड इलेक्ट्रॉन्सची संख्या ______ आहे. The number of unpaired electrons in tetrahedral [Ni(CO)4] complex is ________

In [Ni(CO)4], nickel is in the 0 oxidation state with a 3d8 4s2 configuration. CO is a strong field ligand that causes pairing of electrons, resulting in sp3 hybridization and zero unpaired electrons.

अणुकेंद्रका भोवती दुसऱ्या भ्रमणकक्षेत भ्रमण करणाऱ्या इलेक्ट्रॉनची ऊर्जा - 3.4 eV आहे. त्याची तिसऱ्या भ्रमण कक्षेत ऊर्जा किती ? Energy of the electron revolving around the nucleus in second orbit is - 3.4 eV. What is its energy in third orbit ?

Energy in the nth orbit of a hydrogen-like atom is given by E_n = -13.6 / n² eV. For n=3, E3 = -13.6 / 9 = -1.51 eV.

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व्यावहारिक दृष्ट्या अणूचे सारे वस्तुमान मुख्यत्वे त्याच्या पुढील कणांमध्ये एकत्रित असते... / Practically all the mass of an atom is concentrated in its

Practically all the mass of an atom is concentrated in its nucleus, which consists of protons and neutrons (nucleons). Electrons have negligible mass.

'1 मोल' ही किंमत पुढील कोणत्या किमतीशी समप्रमाणात आहे ? / 1 mole is equal to which quantity from the following?

One mole of a substance contains Avogadro's number of particles (6.022 × 10²³) and has a mass equal to its atomic/molecular mass in grams (e.g., 12g of C-12).

अव्होगाड्रो संख्या ही पुढीलपैकी गोष्टींशी संबंधित असते / The Avogadro number is related to

Avogadro's number represents the total number of constituent particles (atoms or molecules) present in exactly 1 mole of any substance.

कल्सिनेशन प्रक्रियेतून ________ बाहर पडतो. During calcination process

During calcination, ores are heated strongly below their melting point in the absence of air. Depending on the ore type, it can release carbon dioxide (from carbonates) or water (from hydrated oxides).

खालीलपैकी कोणते लुईस आम्ल नाही ? Which of the following is not a Lewis acid?

A Lewis acid is an electron-pair acceptor. Barium chloride (BaCl2) is an ionic compound and acts as a source of chloride ions, not an electron-pair acceptor in the Lewis sense, unlike boron and beryllium halides which have incomplete octets.

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वनस्पती तेलं ही, _______ / Vegetable oils are _______

Vegetable oils are generally triglycerides of unsaturated fatty acids, characterized by carbon-carbon double bonds and liquid state at room temperature.

खालीलपैकी काही ही कोलायडल सोल्सच्या वैशिष्ट्ये आहेत ? The following are some of the properties of the colloidal sols :

Colloidal sols exhibit the Tyndall effect (scattering of light) and Brownian motion (random zigzag motion of particles), which are hallmark properties of colloids.

खालील दिलेल्या विधानापैकी कोणती विधाने बरोबर आहेत ? Which of the following statements are correct?

HF and H2O are polar molecules due to significant electronegativity difference and bent/asymmetrical geometry. CH4 and CO2 are non-polar due to symmetrical geometry cancelling dipoles.

खालीलपैकी कोणती अभिक्रियांकारके अमोनिया तयार करण्यासाठी वापरतात ? Which of the following reactants can be used to prepare ammonia?

Ammonia can be prepared by heating ammonium chloride with calcium hydroxide, through Haber's process using nitrogen and hydrogen, and by the action of water on calcium cyanamide. All three methods are standard chemical preparations of ammonia.

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रुदरफोर्डच्या सुवर्णपत्री प्रयोगाचे एक निरीक्षण. “काही α-कणांचे काही कोनातून विचलन झाले” ह्याचे कारण α-कण वरीलपैकी कोणते/ती विधान/ने बरोबर आहे/आहेत. / One of the observations of Rutherford's thin gold foil experiment was "some α-particles got deflected by some angle". The reason was α-particles. The correct option/s is are

In Rutherford's experiment, alpha particles are positively charged. When they came close to the positive nucleus, they experienced electrostatic repulsion and got deflected.

रुदरफोर्डच्या प्रयोगाचे कोणते निरीक्षण प्लम पुडिंग प्रकृती वापरून समजणे शास्त्रिय दृष्ट्या अशक्य आहे ? / Which of the following observations of Rutherford's experiment is impossible to understand scientifically with the plum pudding model ?

The plum pudding model assumes mass and positive charge are uniformly distributed. Hence, it cannot explain how heavy alpha particles could bounce back (rebound) by colliding with a dense central nucleus.

शास्त्रीय तर्कानुसार. खालीलपैकी कोणती विधाने अचूक असतील.

A cation is formed by losing electrons, making its size smaller than the neutral atom (statement a). An anion is formed by gaining electrons, making its size larger than the neutral atom (statement d).

₁₆S³² ह्या अणुमध्ये, 'M' कवचात ______ इलेक्ट्रॉन असतात.

Sulfur (atomic number 16) has the electronic configuration 2, 8, 6. The shells are K=2, L=8, and M=6. Therefore, the M shell contains 6 electrons.

'अ' गटातील घटकांना 'ब' गटात एकापेक्षा जास्त बरोबर पर्याय उपलब्ध असू शकतात. 'अ' गट 'ब' गट I. 10 इलेक्ट्रॉन्स अ. ²⁰₁₀Ne II. 12 प्रोटॉन्स ब. ²³₁₁Na⁺ III. 12 न्युट्रॉन्स क. ¹⁹₉F⁻ IV. 10 न्युट्रॉन्स ड. ²⁴₁₂Mg²⁺ You may have more than one correct match in Group 'B' for each item in Group 'A'. Group A Group B I. 10 electrons a. ²⁰₁₀Ne II. 12 protons b. ²³₁₁Na⁺ III. 12 neutrons c. ¹⁹₉F⁻ IV. 10 neutrons d. ²⁴₁₂Mg²⁺

Detailed electron, proton, and neutron calculations for Ne, Na+, F-, and Mg2+ match multiple criteria across the groups due to isoelectronic and isotopic relationships.

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कार्बन डायऑक्साइडची पाण्याबरोबर अभिक्रिया होऊन __________ हे बनते. When H2O (l) reacts with CO2 (g) it gives

When carbon dioxide dissolves in water, it forms carbonic acid (H2CO3), a weak acid responsible for the acidic nature of carbonated water.

'M' हे मूलद्रव्य डोबेरीनर त्रिके मध्ये Ca, M आणि Ba हे ________ आहे. / The element M in the Dobereiner triad Ca, M and Ba is ________

In Dobereiner's triads, elements with similar properties were grouped in threes where the atomic mass of the middle element is approximately the mean of the other two. For the triad Calcium (Ca), Strontium (Sr), and Barium (Ba), Strontium (Sr) is the middle element.

काष्ठजन्य अल्कोहोल म्हणजेच / Wood grain alcohol is nothing but

Wood grain alcohol or wood alcohol is chemically known as Methanol (CH₃OH), which was historically obtained by the destructive distillation of wood.

पाण्यात क्लोरीन नेहमी मिसळतात कारण / Water is often treated with chlorine to

Chlorine is a powerful disinfectant used in water treatment to kill harmful disease-causing germs, bacteria, and microorganisms, ensuring safe drinking water.

___________ ह्यामुळे गंजण्याची क्रिया होते. / Corrosion takes place as a result of

Corrosion, such as the rusting of iron, involves a chemical change where metals react with atmospheric oxygen, moisture, and acids to form new chemical compounds like metal oxides.

नैसर्गिक वायुमध्ये ___________ चे प्रमाण मुख्यत्वे करून असते. / Natural gas mainly consists of

Natural gas is a naturally occurring hydrocarbon gas mixture consisting primarily of Methane (CH4), often up to 70-90% of its composition.

नैसर्गिक स्रोतातील कोणत्या घटकापासून चरबी आणि तेल मिळते ? / Fats and oils belong to the naturally occurring group of compounds called

Fats and oils belong to a naturally occurring group of lipid compounds, specifically triglycerides, which are esters of glycerol and fatty acids.

वरील उताऱ्यावरून खालील निष्कर्ष काढता येतो : The following conclusion can be drawn from the above passage :

Ammonium chloride dissolves in water and is also a well-known substance that undergoes sublimation upon heating, changing directly from solid to gas.

अमोनियम मूलकाच्या अस्तित्वामुळे खालील निरीक्षणे आढळतात The correct observations due to the presence of ammonium ions are

Ammonium ions (NH₄⁺) turn moist red litmus blue (due to basic ammonia gas released), turn turmeric paper brownish/reddish-brown, and give dense white fumes of ammonium chloride with a glass rod dipped in dilute hydrochloric acid.

कु. रियाला अपेक्षित निरीक्षण मिळाले नाही, कारण तिने / Ms. Riya did not get the desired observation, because she brought

Gas tests using litmus paper require the litmus paper to be moist so that the basic gas (NH₃) can dissolve and form ions to show the color change. Riya failed because she applied it directly to the solution instead of the evolved gas or used dry paper incorrectly.

श्री रवीला अपेक्षित निरीक्षण मिळाले नाही, कारण त्याने / Mr. Ravi did not get the desired observation, because he brought

Turmeric paper is used as an indicator for bases. Ravi brought it in contact with the gas from the left-hand test tube where acidic or different gases might be evolving, leading to no desired basic gas observation.

दाट सफेद वाफा तयार झाल्या, कारण / Observations about white dense fumes are seen

Dense white fumes are produced due to chemical reactions and specific property changes like the sublimation of ammonium chloride when heated/reacted.

फॅरेडेचा विद्युत अपघटन नियम कशाशी संबंधित आहे ? Faraday's Laws of electrolysis are concerned with

Faraday's laws of electrolysis state that the amount of chemical change during electrolysis is proportional to the quantity of electricity passed, which is directly related to the equivalent weight of the substance.

ज्या केंद्रभागांचे अणुक्रमांक आणि अणु वस्तुमान विविध असतात, पण न्यूट्रॉनची संख्या समान असेल, तर त्यांना ________ म्हणतात. If nuclides have different atomic numbers and different atomic masses but the same number of neutrons, then they are known as

Nuclides with different atomic numbers and mass numbers but the exact same number of neutrons are known as Isotones.

स्थिरांकाचे (a) चे एकक ______ व्हॅन डर वाल्स. A unit of Van der Waals constant (a) is

Van der Waals constant 'a' corrects for intermolecular forces of attraction in real gases. Its SI/derived unit is pressure times volume squared per mole squared, which is kPa dm⁶ mol⁻².

ज्या सामूल्य (pH) ला प्रथिण कलिळांवर असलेला भार विरुद्ध होतो त्याला ____________ असे म्हणतात. / The pH at which the charge on protein colloid is reversed is called

The pH at which the net charge on a protein colloid or amino acid is zero and the electrophoretic movement is zero is called the Isoelectric point.

N₂ + 3H₂ ⇌ 2NH₃ + Heat लि चॅटलीअर चे तत्व असे सुचित करते की ____________ असेल तर वरील रासायनिक अभिक्रियेत जास्तीत जास्त अमोनिया वायु तयार होईल. / N₂ + 3H₂ ⇌ 2NH₃ + Heat The Le Chatelier's principle suggests that ____________ are required to drive the reaction to the right and thus form NH₃.

According to Le Chatelier's principle, since the formation of ammonia is exothermic (releases heat) and decreases the number of moles of gas, high pressure and low temperature favor the forward reaction to maximize yield.

pH मापणी ही पाणी द्रावणांची अम्लता व अलकधर्मिता मोजण्याकरिता वापरली जाते. ही मापणी हाइड्रोजन आयन (H+) चे संकेंद्रणावर आधारित असते. खालीलपैकी काय अम्ल नाही ? The pH scale, used to measure acidity and alkalinity of water solutions, is based on concentration of hydrogen ions (H+). Which of the following is not acidic ?

Human blood is slightly alkaline with a pH of around 7.4, whereas bananas, milk, and tomatoes are acidic in nature.

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सौर किंवा प्रकाश रासायनिक अभिक्रियेत सक्रियकरण ऊर्जा ही ____________ अवलंबून असते. The energy of activation depends upon ___________ in photochemical reaction.

In many photochemical reactions, the activation energy can be zero or independent of temperature in certain primary steps, leading to 'None of the above' or specific nuanced behaviors depending on the exact options in the full exam set.

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निसर्गात, ____________ हे सौर/प्रकाश रासायनिक अभिक्रियेचे उदाहरण आहे. In nature, ____________ is an example of photochemical reaction.

Photosynthesis in plants is the most prominent natural example of a photochemical reaction where solar energy is converted into chemical energy.

पुढील दोन विधानांपैकी कोणते अयोग्य आहे ? अ. अणु अंक म्हणजे अणु केंद्रातील एकूण प्रोटॉन्सची संख्या. ब. अणु वस्तुमान म्हणजे अणु केंद्रातील एकूण प्रोटॉन्स व न्यूट्रॉन्सची संख्या. Which one of the following statements is/are incorrect ? a. The number of protons in a nucleus is called its atomic number. b. The total number of protons and neutrons constitute its mass number.

Atomic number is indeed defined as the number of protons in the nucleus, and mass number is the sum of protons and neutrons. Both statements are correct, meaning none is incorrect.

जस जशी रासायनिक अभिक्रिया होत रहाते वेळेनुसार तिचा वेग _________ With the progress of any chemical reaction, the rate of the chemical reaction _________ with time.

The rate of a chemical reaction generally decreases with time as the concentration of reactants decreases and gets converted into products.

नैसर्गिक रबर हा एक _________ चा पॉलिमर् आहे. Natural rubber is a polymer of _________

Natural rubber is a natural polymer made up of repeating units of isoprene (2-methyl-1,3-butadiene).

फायर एक्स्टिंग्विशर म्हणून कशाचा उपयोग होऊ शकतो ? What can be used as a fire extinguisher ?

Various agents like water, carbon dioxide (CO2), and foam can be used as fire extinguishers depending on the type of fire.

व्याश्लेषणाचा दर हा — च्या मदतीने वर्धित केला जाऊ शकतो Rate of dialysis can be enhanced with the help of

Dialysis is the process of separating colloidal particles from ions using a semipermeable membrane. Its rate can be enhanced by applying an electrical field (known as electro-dialysis), but magnetic, electromagnetic, or nuclear fields do not enhance simple dialysis.

पायस (इमल्शन) प्राप्तीकरीता कोणत्या पदार्थाचे तयार करण्याचे समांतर पद्धती तत्व वापरले जाऊ शकते ? Emulsions can also be prepared by using the principle similar to the preparation of

Emulsions are colloidal systems of two immiscible liquids and can be prepared using principles similar to the preparation of aerosols, where one phase is dispersed in another.

दुधाच्या पृष्ठभागावर प्राप्त होणारे दुग्धसारण हे The cream obtained on the surface of milk is

The cream that rises to the top of milk consists of fat globules dispersed in an aqueous medium, forming an emulsion where fats are the dispersed phase.

मुळे वायुरूपातील द्रवरूपाच्या अपस्करणातुन एरोसोल तयार होतात Aerosols are dispersions of liquids in gases formed by

Aerosols are colloidal systems where liquid droplets or solid particles are dispersed in a gas. The formation described does not match standard mechanical aerosol generation methods listed in a, b, or c.

हा अभिकर्ता ओल्या मातीच्या आल्कधर्मी पेप्टीकरणाच्या प्रक्रियेत कार्यक्षम असतो In the process of alkaline peptization of clays ________ is the active agent.

Alkaline peptization of clays typically involves peptizing agents like sodium hydroxide or sodium carbonate which provide hydroxyl ions or specific ions, but none of the specific radicals/ions listed as a, b, or c are the sole active agents in the generalized sense required here.

सॉलिड फुड पॅकेजिंगसाठी सर्वात अधिक वापरली जाणारी व स्वस्त प्लास्टिक फिल्म कशाची असते ? The most common and least expensive plastic film used for packaging of solid food materials is

Polyethylene is the most widely produced and least expensive plastic, making it the most common film used for food packaging.

ग्लुकोज मधे कार्बनची टक्केवारी __________ आहे. / The percentage of carbon in glucose is

The molecular formula of glucose is C6H12O6. Molar mass = (6*12) + (12*1) + (6*16) = 72 + 12 + 96 = 180 g/mol. Percentage of carbon = (72 / 180) * 100 = 40%.

रासायनिक पदार्थांचा आर्द्रताग्राही स्वभावधर्म दर्शवितो की तो चांगला The hygroscopic nature of chemical substance indicates that it is a good

Hygroscopic substances absorb moisture from the surrounding air, making them effective drying agents (desiccants).

α-कण ह्यांनी शोधून काढले : α-particles were discovered by

Alpha particles were identified and named by Ernest Rutherford during his pioneering work on radioactivity.

पुढील दोन विधानांपैकी कोणते योग्य आहे ? Which of the following two statements is correct ?

Statement (a) claiming chemistry is the 'superior most science' is subjective and unscientific. Statement (b) is correct because biochemical reactions are fundamental to life; without chemistry, biological life cannot exist.

पुढील विधानांपैकी कोणते अयोग्य आहे ? Which of the following statements is incorrect ?

Both statements are incorrect. Chemical processes like decomposition continue in a human body after death. Also, chemistry alone cannot 'cure' bioterrorism, which is a socio-political and security issue rather than a chemical ailment.

पुढील विधानांपैकी कोणते योग्य आहे ? Which of the following statements is correct ?

Statement (a) is incorrect because synthetic medicines are not universally 'more useful' than natural ones (both have pros and cons). Statement (b) is incorrect because harmful effects of chemicals are controlled by regulations, safety protocols, and antidotes, not automatically by 'helpful chemicals'.

खालीलपैकी कार्बनचे ऑलॅट्रोप कुठले ते सांगा? / The allotropes of carbon are :

Diamond, fullerenes, graphite, and chaoite are well-known allotropes of carbon. Carbon halides are compounds, not allotropes.

ऑक्सीजन निसर्गात किती आइसोटोप्स मध्ये आढळतो? / Oxygen occurs in nature in ________ isotopic forms.

Oxygen occurs naturally in three stable isotopic forms: Oxygen-16, Oxygen-17, and Oxygen-18.

खालील विधानांची सत्यता पडताळा. 'अन्न संरक्षण समिती' प्रकाशन 398 द्वारा रासायनिक पदार्थाच्या अन्नप्रक्रियेतील वापर संबंधी खालील मार्गदर्शक तत्वे दिलेली आहेत. त्यांची सत्यता पडताळा. / Which of the following statements are true ? The guidelines for "the use of chemical additives in food processing" by Food Protection Committee in publication 398 include :

According to the Food Protection Committee publication 398, chemical additives include antioxidants for nutrients, antimicrobial agents and inert gases for preservation, coloring/flavoring agents for appearance, and buffers.

खालीलपैकी कुठले विधान सत्य आहे ? / Which of the following statements is true ?

Indigo-blue is a well-known natural organic dye extracted from plants. Alizarin can be natural but is commercially a synthetic anthraquinone dye, making statement (b) false as stated or vice versa depending on strict textbook definitions, but standard text treats Indigo as natural.

सुक्रोज चे पाण्याबरोबर संयोग होऊन पृथःक्करण झाल्यास समप्रमाणात कुठले मिश्रण तयार होते ? / Upon hydrolysis, sucrose yields equimolar mixture of :

Hydrolysis of sucrose (a disaccharide) breaks it down into an equimolar mixture of glucose and fructose.

सिमेंटची निर्मिती ही खालीलपैकी कुठल्या घटकांपासून झालेली आहे ? / The composition of cement is :

Cement is primarily composed of calcium oxide (CaO), silicon dioxide (SiO2), and aluminium oxide (Al2O3).

कोणते मिश्रण नाही ? What is not a mixture ?

Water (H2O) is a chemical compound, not a mixture, as its constituents are combined in a fixed chemical proportion.

पुढील दोन विधानापैकी कोणते योग्य आहे ? / Which of the following two statements is correct ?

The chairperson and members of the National Human Rights Commission (NHRC) are appointed by the President on the recommendations of a six-member committee consisting of the Prime Minister, Lok Sabha Speaker, Deputy Chairman of Rajya Sabha, Leaders of Opposition in both Houses, and Union Home Minister.

काही नैसर्गिकरित्या आढळणारे acids (आम्ल) त्यांच्या स्रोतासह दिलेले आहेत. चुकीची जोडी ओळखा : (a) व्हिनेगर - अ‍ॅसिटिक अ‍ॅसिड (b) संत्री - सायट्रिक अ‍ॅसिड (c) चिंच - टार्टारिक अ‍ॅसिड (d) टोमॅटो - ऑक्झॅलिक अ‍ॅसिड (e) आंबट दूध (दही) - लॅक्टिक अ‍ॅसिड (f) लिंबू - सायट्रिक अ‍ॅसिड (g) किटकाचा डंख - मेथॅनॉइक अ‍ॅसिड (h) नेटलचा डंख - सल्फ्युरिक अ‍ॅसिड Some naturally occurring acids are given below with their sources. Identify the incorrect pair : (a) Vinegar - Acetic acid (b) Oranges - Citric acid (c) Tamarind - Tartaric acid (d) Tomatoes - Oxalic acid (e) Sour milk (curds) - Lactic acid (f) Lemons - Citric acids (g) Ant sting - Methanoic acid (h) Nettle sting - Sulphuric acid

Nettle sting contains formic acid (methanoic acid), not sulfuric acid. Sulfuric acid is a strong mineral acid, whereas plant stings contain organic acids.

गन पावडर हे एक मिश्रण आहे जे पेटविल्यास रासायनिक प्रक्रिया होऊन स्फोट होतो. या मिश्रणात पुढील बाबी असतात : (a) पोटॅशियम नायट्रेट (b) कोळशाची पावडर (c) सल्फर (d) सोडिअम कार्बोनेट (e) कॅल्शिअम सल्फेट

Gunpowder is a traditional explosive mixture composed of potassium nitrate (saltpeter, acting as oxidizer), charcoal (fuel), and sulfur (fuel and low ignition point).

खालील धातू विचारत घ्या. (a) प्लॅटिनम (b) सोने (c) तांबे (d) शिसे चढत्या धनतेनुसार त्यांची क्रमवारी लिहा : Consider the following metals : (a) Platinum (b) Gold (c) Copper (d) Lead Their correct arrangement in the increasing order of density is :

Platinum has the highest density among the given metals, followed by gold, lead, and copper. Arranging them in increasing order gives copper, lead, gold, and platinum.

डायक्लोरोडिफेनिलट्रायकलोरो इथेन (डीडीटी) सर्वप्रथम क्लोरेनिडेटेड ऑरगॅनिक कीटकनाशक असून परिणामकारक कीड नष्ट करणाऱ्या त्याच्या गुणांकास्ता पॉल मुलर यांना मेडीसीन व फिजिऑलॉजीचे 1948 चे नोबेल पारितोषिक प्रदान करण्यात आले. वरील कोणती विधाने खरी आहेत ? Dichlorodiphenyl Trichloro Ethane (DDT) is the first chlorinated organic insecticide for the discovery of its effectiveness as an insecticide Paul Muller was awarded Nobel Prize in Medicine and physiology in 1948. Which of the above statements are correct ?

DDT is a historic synthetic insecticide credited with stopping vector-borne diseases like malaria and typhus. It affects aquatic life negatively and persists in animal fatty tissues due to poor metabolism.

___________ औषधी द्रव्य नैसर्गिक उत्पादन आहे.

Natural medicinal drugs are obtained directly from plant or animal sources (like quinine, morphine, or penicillin derived sources), serving as natural products compared to fully synthetic drugs.

रेणूमध्ये अणू _________ बलाद्वारे एकत्रित ठेवले जातात.

Atoms in a molecule are held together by chemical bonds formed through electron sharing or transfer.

बटाटा चीप्स उत्पादक, चीप्स बॅगेत भरताना त्यासोबत एक वायू भरतात, जेणेकरून चीप्स ऑक्‍सिडाईझ होत नाहीत. खालीलपैकी कोणता वायू यासाठी वापरला जातो ?

Nitrogen gas is flushed into potato chip bags to displace oxygen, preventing the chips from getting rancid through oxidation.

पांढऱ्या कपड्यावर पडलेला वरणाचा डाग साबण लावल्यावर लालसर तपकिरी (रेंडिश ब्राउन) होतो. तो अधिक पाण्याने धुतल्यावर पुन्हा पिवळा होतो. तो आधी लालसर तपकिरी (रेंडिश ब्राउन) होतो कारण - A stain of curry on a white cloth becomes reddish brown when soap is scrubbed on it. It turns yellow again when the cloth is washed with plenty of water. It had turned reddish brown because :

Curry contains turmeric, which acts as a natural indicator. Soap is basic in nature, changing turmeric's color to reddish brown, which reverts when diluted.

जर फुग्यामध्ये कोरडी हवा भरली तर त्यामध्ये असलेल्या 79% नायट्रोजन आणि 21% ऑक्सिजन पैकी कोणत्या घटकांची 25° सेल्सियसला सर्व प्रथम बाहेर गळती होईल? If balloon is filled with dry air which contains mixture of 79% N₂ and 21% O₂ at 25°C then which component of the air will effuse out first ?

According to Graham's law of effusion, the rate of effusion of a gas is inversely proportional to the square root of its molar mass. Since Nitrogen (M = 28) is lighter than Oxygen (M = 32), Nitrogen effuses out first.

खालीलपैकी शुद्ध पदार्थ कोणता ? / Indicate which of the following is a pure substance ?

Iron (लोह) is a chemical element and therefore a pure substance, whereas gasoline, cow's milk, and sea water are mixtures containing multiple components.

रिकामी जागा योग्य शब्दाने भरा. एका शासकीय नोकरास लाच घेताना पकडण्यास्तव तयार केलेल्या सापळ्यात फेनाँफथेलीन पावडर लावलेल्या नोटा वापरल्या गेल्या. गुन्ह्यासाठी पुरावा म्हणून त्यावर शिंपडलेले सोडियम कार्बोनेट __________ रंगाचे व्हावयास हवे. (1) निळे (2) जांभळे (3) लाल (4) काळे Fill in the blank appropriately. A trap laid for apprehending a Govt. employee taking bribe used phenophthelein powder coated currency notes. A solution of sodium carbonate sprinkled on the notes must turn __________ for lending proof for the crime. (1) blue (2) purple (3) red (4) black

Phenolphthalein is colorless in acidic/neutral medium and turns pink/purple in basic medium. Sodium carbonate is a basic salt, turning phenolphthalein purple/pink.