Class 12 Chemistry – Daily Revision MCQ (English Medium)
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What percentage of the total volume of an fcc (ccp) unit cell is actually occupied by particles?
Chapter 1: Solid State
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Answer: C. 74%
In fcc/ccp (and hcp) lattices the packing efficiency is 74%; the remaining 26% is empty (void) space.Calcium chloride (CaCl₂) dissociates completely in water. Its expected van't Hoff factor (i) is:
Chapter 2: Solutions
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Answer: A. 3
CaCl₂ → Ca²⁺ + 2Cl⁻ gives 3 ions per formula unit, so for complete dissociation i = 3.Which pair of substances, dissolved together in water, forms an acidic buffer solution?
Chapter 3: Ionic Equilibria
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Answer: B. CH₃COOH and CH₃COONa
An acidic buffer contains a weak acid and its salt with a strong base, e.g. acetic acid with sodium acetate.The potential of the standard hydrogen electrode (SHE), used as the primary reference electrode, is taken as:
Chapter 5: Electrochemistry
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Answer: D. 0 V (zero, by convention)
The SHE is the primary reference electrode and its potential is arbitrarily taken as zero at all temperatures.For a zero order reaction, the rate of reaction:
Chapter 6: Chemical Kinetics
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Answer: C. does not depend on the reactant concentration
For a zero order reaction, rate = k[A]⁰ = k, so the rate stays the same whatever the reactant concentration.What is the oxidation state of iron in K₄[Fe(CN)₆]?
Chapter 9: Coordination Compounds
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Answer: B. +2
The complex ion is [Fe(CN)₆]⁴⁻: x + 6(−1) = −4, so x = +2.Methyl bromide (CH₃Br) is heated with metallic sodium in dry ether (Wurtz reaction). Which alkane is formed?
Chapter 10: Halogen Derivatives
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Answer: A. Ethane
In the Wurtz reaction two alkyl groups join (R–R), doubling the carbon count: 2CH₃Br + 2Na → CH₃–CH₃ + 2NaBr.Heating with chloroform and alcoholic KOH to give a foul-smelling isocyanide (carbylamine test) is a test for:
Chapter 13: Amines
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Answer: D. primary amines only
Only primary amines (aliphatic or aromatic) give foul-smelling isocyanides with chloroform and alcoholic KOH.In the DNA double helix, guanine pairs with cytosine through how many hydrogen bonds?
Chapter 14: Biomolecules
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Answer: C. Three
Guanine forms three hydrogen bonds with cytosine, while adenine forms two with thymine.Who put forward the 12 principles of green chemistry and is known as the father of green chemistry?
Chapter 16: Green Chemistry and Nanochemistry
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Answer: B. Paul T. Anastas
Paul T. Anastas enunciated the twelve principles of green chemistry; Feynman and Taniguchi are linked with nanotechnology.
Class 12: MCQ in other subjects
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All questions are written by PadhaiNotes in our own words from the chapters of the official Maharashtra State Board Balbharati textbook (ebalbharati.in). Each question shows its chapter.