Science (English Medium) इयत्ता १२ - CBSE Important Questions for Chemistry

Write one similarity and one difference between the chemistry of lanthanoid and actinoid elements.

What is Lanthanoid contraction?

On the basis of crystal field theory, write the electronic configuration for d⁴ ion if ∆₀ < P.

What type of deviation is shown by a mixture of ethanol and acetone? Give reason.

The following data were obtained during the first order thermal decomposition of SO₂Cl₂ at a constant volume :

SO₂Cl₂ (g) → SO₂ (g) + Cl₂ (g)

Calculate the rate constant.

(Given : log 4 = 0.6021, log 2 = 0.3010)

The conversion of molecules A to B follow second order kinetics. If concentration of A is increased to three times, how will it affect the rate of formation of B?

Give reasons: Transition metals show variable oxidation states.

Complete the following equation : MnO₄^- + 8H⁺ + 5e^- →

How do you prepare:

Actinoid elements show wide range of oxidation states.

Account for the following : Nitrogen does not form pentahalide.

Draw the structure of the semicarbazone of ethanal.

Write chemical test to distinguish between the following compounds:

Phenol and Benzoic acid

Why is the α-hydrogens of aldehydes and ketones are acidic in nature?

Account for the following:

Although the amino group is o, p-directing in aromatic electrophilic substitution reactions, aniline on nitration gives a substantial amount of m-nitroaniline.

Give simple chemical tests to distinguish between the following pair of compounds:

Benzaldehyde and Benzoic acid

What is Hinsberg's reagent?

Give reasons for the following:

Ammonolysis of alkyl halides is not a good method to prepare pure primary amines.

State Henry’s law.

State Henry's law.

Define limiting molar conductivity.