List of top Questions asked in CBSE CLASS XII- 2026

When a coordination compound \( CoCl_{3} \cdot 6NH_{3} \) is mixed with excess of \( AgNO_{3} \) solution, 3 moles of \( AgCl \) are precipitated per mole of the compound. Write the structural formula of the complex, IUPAC name, its hybridisation and magnetic behaviour on the basis of valence bond theory.
Why are magnesium blocks fixed to the iron pipelines carrying water?
Why are the products of electrolysis different for the electrolysis of aqueous solution of \( AgNO_{3} \) with silver electrodes and electrolysis of aqueous solution of \( AgNO_{3} \) with platinum electrodes?
Why is direct current (DC) not used to measure the resistance of an ionic solution?
What happens when: p-fluorotoluene is treated with \( CrO_{3} \) in the presence of acetic anhydride followed by hydrolysis with aqueous acid?
What happens when: Phthalic acid is treated with \( NH_{3} \) followed by heating?
Draw the structure of the major product in the following reaction: \( CH_{3}CH = C(CH_{3})_{2} + HBr \rightarrow \)
What happens when: Propanenitrile is treated with phenyl magnesium bromide followed by hydrolysis?
Write the structures of A, B and C in the following reaction:
Draw the structure of the major product in the following reaction:
Write the structures of A, B and C in the following reaction:
Write IUPAC name of the following compound : \( [Cr(NH_{3})_{4} (ONO)Cl] NO_{3} \)
Write IUPAC name of the following compound : \( Na[Ag(CN)_{2}] \)
What are the hydrolysis products of the following ? Lactose
State the condition under which a bimolecular reaction may be kinetically a first order reaction.
Explain the following with the help of Henry’s law : (i) Bends (ii) Anoxia
What are the hydrolysis products of the following ? DNA containing Thymine
Assertion (A) : Diazonium salts of aromatic amines are more stable than those of aliphatic amines.
Reason (R) : Diazonium salts of aliphatic amines undergo resonance.
Reactions of which order will show the rate to be independent of the concentration of the reactant ? Give one example of this order.
Assertion (A) : For complex reaction, order of reaction is given by the slowest step.
Reason (R) : Order of a reaction is an experimental quantity.
Assertion (A) : Alcohols act as Bronsted bases as well as Bronsted acids.
Reason (R) : It is due to the presence of unshared electron pairs on oxygen atom and presence of polar \( O - H \) bond.
Assertion (A) : \( E^{\circ}_{Sc^{3+}/Sc^{2+}} \) has low value.
Reason (R) : Because of the stability of \( Sc^{3+} \) ion which has a noble gas configuration.
When a liquid and its vapour are at equilibrium and the pressure is suddenly decreased :
The rate of a first order reaction is \( 5.6 \times 10^{-4} \, mol \, L^{-1} \, s^{-1} \), when the concentration of reactant is \( 0.2 \, mol \, L^{-1} \). The rate constant \( 'k' \) is :
Consider the following cell at \( 298 \, K \): \( Mg (s) \mid Mg^{2+} (1.0 \, M) \parallel Cu^{2+} (1.0 \, M) \mid Cu (s) \). How can we increase the emf of the cell using the same substances ?