PUC Science 2nd PUC Class 12 - Karnataka Board PUC Question Bank Solutions for Chemistry

Explain the fact that in aryl alkyl ethers 

1. the alkoxy group activates the benzene ring towards electrophilic substitution and
2. it directs the incoming substituents to ortho and para positions in the benzene ring.

Why does O₃ act as a powerful oxidising agent?

How is O₃ estimated quantitatively?

Which aerosols deplete ozone?

Determine the osmotic pressure of a solution prepared by dissolving 2.5 × 10⁻² g of K₂SO₄ in 2L of water at 25°C, assuming that it is completely dissociated.

(R = 0.0821 L atm K⁻¹ mol⁻¹, Molar mass of K₂SO₄ = 174 g mol⁻¹)

Give the structures of A, B and C in the following reactions:

Although phenoxide ion has more number of resonating structures than carboxylate ion, carboxylic acid is a stronger acid than phenol. Give two reasons.

How would you account for the following:

The chemistry of actinoids is more complicated as compared to lanthanoids.

Write the structures of main products when benzene diazonium chloride `(C_6H_5N_2^(+)Cl^-)`reacts with the following reagents:

CuCN/KCN

Write the structures of main products when benzene diazonium chloride `(C_6H_5N_2^(+)Cl^-)`reacts with the following reagents:

H₂O

Write the structures of main products when benzene diazonium chloride `(C_6H_5N_2^(+)Cl^-)`reacts with the following reagents:

CH₃CH₂OH

Give a reason for the following: 

Actinoids show irregularities in their electronic configurations.

Write the structures of A, B and C in the following:

Why pKa of F-CH₂-COOH is lower than that of Cl−CH₂−COOH?

What happens when the external pressure applied becomes more than the osmotic pressure of solution?

Blood cells are isotonic with 0.9% sodium chloride solution. What happens if we place blood cells in a solution containing

(i) 1.2% sodium chloride solution?

(ii) 0.4% sodium chloride solution?

How would you account for the following:

Actinoid contraction is greater than lanthanoid contraction.

Why do actinoids show a wide range of oxidation states?

Write on similarity between the chemistry of lanthanoids and actinoids.

Distinguish between the following : Benzoic acid and methyl benzoate