List of top Chemistry Questions asked in CBSE CLASS XII

An azeotropic solution of two liquids has a boiling point lower than either of them when it:
The relative lowering of vapor pressure of an aqueous solution containing a non-volatile solute is 0.0225. The mole fraction of the non-volatile solute is:
Phenol dimerises in benzene having van’t Hoff factor 0.54. Its degree of association is:
Assertion (A): When NaCl is added to water, elevation in boiling point is observed. Reason (R): Elevation in boiling point is a colligative property.
Assertion (A): p-Nitroaniline is a weaker base than p-toluidine. Reason (R): The electron-withdrawing effect of \(-NO_2\) group in p-nitroaniline makes it a weaker base.
Phenol does not undergo nucleophilic substitution reaction easily due to:
Which of the following compounds will not react with benzene sulphonyl chloride?
 
Aniline on reaction with Bromine water gives:
Assertion (A): Aliphatic primary amines can be prepared by Gabriel phthalimide synthesis. Reason (R): Alkyl halides undergo nucleophilic substitution with anion formed by phthalimide.
Assertion (A): Diazonium salts of aromatic amines are more stable than those of aliphatic amines. Reason (R): Diazonium salts of aliphatic amines show resonance.
Identify the tertiary amine from the following:
Phenol on reaction with aqueous bromine at room temperature gives:
Ethanol on heating with conc. H\(_2\)SO\(_4\) at 413 K gives:
Dehydration of tertiary alcohols with Cu at 573 K gives:
CH\(_3\)-O-CH\(_3\) when treated with excess HI gives:
Assertion (A): p-nitrophenol is less acidic than phenol.
Reason (R): Nitro group is electron-withdrawing and helps in the stabilization of p-nitrophenoxide ion.
Match the reagents required for the given reactions: I. Oxidation of primary alcohols to aldehydes (p) \(NaBH_4\)
II. Butan-2-one to Butan-2-ol (q) 85% phosphoric acid at 440 K
III. Bromination of Phenol to 2, 4, 6- (r) PCC Tribromophenol
IV. Dehydration of propan-2-ol to (s) Bromine water propene
Consider the following reaction:
benzyl alcohol (C6H5CH2OH)
The major product obtained is:
Which functional groups of glucose interact to form cyclic hemiacetal leading to pyranose structure?
Nucleotides are composed of:
Which of the following acids represents Vitamin C?
‘Scurvy’ is caused by the deficiency of vitamin:
Two among the three components of DNA are $\beta$-D-2-deoxyribose and a heterocyclic base. The third component is:
The specific sequence in which amino acids are arranged in a protein is called:
Which of the following cells is used in hearing aids?