List of top Questions asked in CBSE CLASS XII- 2026

Assertion (A): Transition metals show their highest oxidation state with oxygen.
Reason (R): The ability of oxygen to form multiple bonds to metals.
Assertion (A): Order of reaction is applicable to elementary as well as complex reactions.
Reason (R): For a complex reaction, molecularity has no meaning.
Assertion (A): Monobromination of aniline can be conveniently done by protecting the amino group by acetylation.
Reason (R): Acetylation increases the activation effect of the amino group.
Consider the following compounds : Chlorobenzene (I), 2,4,6-trinitrochlorobenzene (II), 2,4-dinitrochlorobenzene (III), 4-nitrochlorobenzene (IV).
The correct order of increasing rate of nucleophilic substitution reactions of these compounds is :
1 mole of liquid A and 2 moles of liquid B make a solution having a total vapour pressure 40 torr. The vapour pressure of pure A and pure B are 30 torr and 45 torr respectively. The above solution :
Assertion (A): Ethers have lower boiling points than the boiling points of alcohols.
Reason (R): This is due to the presence of hydrogen bonding in alcohols.
Which of the following transition metals shows +1 and +2 oxidation states ?
The mole fraction of a solute in 2·0 molal aqueous solution is :
Which of the following product is formed when salicylic acid is treated with $\mathrm{(CH_3CO)_2O}$ in the presence of acid ?
Which reagent is used to distinguish between primary, secondary and tertiary amines ?
The correct order of decreasing basic strength in aqueous solution of the following is :
On electrolysis of very dilute aqueous solution of NaCl using platinum electrodes :
The oxidation number of Pt in $\mathrm{[Pt(en)_2Cl_2]^{2+}}$ is :
According to Werner's theory, the primary valencies of the central metal atom :
Consider the following compounds : Chlorobenzene (I), 2,4,6-trinitrochlorobenzene (II), 2,4-dinitrochlorobenzene (III), 4-nitrochlorobenzene (IV). The correct order of increasing ease of nucleophilic substitution reactions of these compounds is :
On hydrolysis, which of the following carbohydrates gives only β-glucose ?
Which of the following transition metals shows +1 and +2 oxidation states ?
The correct order of decreasing basic strength in aqueous solution of the following is :
The mole fraction of a solute in 2.0 molal aqueous solution is :
On electrolysis of very dilute aqueous solution of NaCl using platinum electrodes :
Which of the following product is formed when salicylic acid is treated with (CH3CO)2O in the presence of acid ?
The oxidation number of Pt in [Pt(en)2Cl2]2+ is :
Which reagent is used to distinguish between primary, secondary and tertiary amines ?
Draw a neat diagram of megasporangium of an angiosperm and label any six parts.
Read the following statements : Assertion (A) and Reason (R).
Assertion (A) : General forces such as social, political, legal and technological conditions affect an individual firm only indirectly.
Reason (R) : General forces have an impact on all business enterprises, in contrast to, specific forces that affect individual firms directly and immediately in their day-to-day working.
Choose the correct alternative from the following :