List of top Chemistry Questions asked in CBSE CLASS XII

During electrolysis of an aqueous solution of NaCl:
Assertion (A): For a Daniell cell, Zn/Zn$^{2+}$(1M) || Cu$^{2+}$(1M)/Cu with \( E_{\text{cell}} = 1.1 \, V \), if the external opposing potential is more than 1.1 V, the electrons flow from Cu to Zn.
Reason (R): Cell acts like a galvanic cell.

Considering the strength of the ligand, the highest excitation energy will be observed in:

On adding AgNO\(_3\) solution to 1 mole of CoCl\(_3\)·4NH\(_3\), one mole of AgCl is precipitated. The secondary valency of Co is:
Which of the following ligands forms a chelate complex?
Ligand EDTA\(^{4-}\) is an example of a:
Which of the following ligands is an ambidentate ligand?

The most stable complex among the following is:

Assertion (A): Rate of reaction decreases with increase in temperature. Reason (R): Number of effective collisions increases with increase in temperature.
In the Arrhenius equation, when log k is plotted against 1/T, a straight line is obtained whose:
A reaction A$_2$ + B$_2$ → 2AB occurs by the following mechanism:
A$_2$ → A + A (slow)
A + B$_2$ → AB + B (fast)
A + B → AB (fast)
Its order would be:
For the reaction X + 2Y → P, the differential form equation of the rate law is:
The addition of a catalyst during a chemical reaction alters which of the following quantities of the reaction?
In the Arrhenius equation, when log k is plotted against 1/T, a straight line is obtained whose:

For a chemical reaction A → B, the rate doubles when the concentration of A is increased four times. The order of reaction is

The half-life of a first-order reaction with a rate constant (\( k \)) of 3 min\(^{-1}\) is:
For the elementary reaction \( P \to Q \), the rate of disappearance of ‘P’ increases by a factor of 8 upon doubling the concentration of ‘P’. The order of the reaction with respect to ‘P’ is:
The correct Mathematical expression of Arrhenius equation is:
The formation of cyanohydrin from an aldehyde is an example of:
The reaction of an alkyl halide with sodium alkoxide forming ether is known as:
Assertion (A): The pKa} of ethanoic acid is lower than that of C1} – CH2} – COOH.
Reason (R): Chlorine shows electron withdrawing (–I) effect which increases the acidic character of C1} – CH2} – COOH.

Williamson's synthesis of preparing dimethyl ether is a/an:

Assertion (A): Aniline is a stronger base than ammonia.
Reason (R): The unshared electron pair on nitrogen atom in aniline becomes less available for protonation due to resonance.

If amines are arranged in increasing order of their basic strength in gaseous phase, the correct order will be:

The chemical test which can be used to distinguish between ethanamine and aniline is: