Account for the following:

(i) BiCl₃ is less covalent than PCl₃

(ii) O₃ acts as a powerful oxidising agent.

(iii) F₂ is a stronger oxidising agent than Cl₂

3

(a)

Give reasons for each of the following:

(a) Sulphur in vapour state exhibits paramagnetic behaviour.

(b) Hydrogen fluoride is weaker acid than hydrogen chloride in water.

(c) NH₃ has higher proton affinity than PH₃.

3

(a)

Describe the following about halogen family (group 17 elements):

(i) Relative oxidising power

(ii) Relative strength of their hydrides

(iii) Oxyacids and their related oxidising ability.

3

(a)

An organic compound A gives a brick red flame on performing flame test. The compound gives the following tests also
I. It gives smell of chlorine when placed in moist air.
II. If KI and CH₃COOH are added to the solution of the compound a violet colour is observed.
Identify the compound and write the chemical reactions for the steps (I) and (II).

3

(a)

Give reasons for each of the following observations
I. Only higher members of the group 18 of the periodic table are expected to form compounds.
II. NO₂ readily forms a dimer whereas ClO₂ doesn’t.

3

(a)

Give reasons for the following observations
I. SF₆ is used as gaseous electrical insulators.
II. S exhibit greater tendency for catenation than selenion.
III. The electron gain enthalpy value of F₂ is less negative than chlorine.

3

(a)

Bleaching of flowers by Cl₂ is permanent, by SO₂ it is temporary. Explain?

3

(a)

Hydrogen halides are covalent compounds but their aqueous solutions can conduct electric current. Explain.

3

(a)

Which of the halogens (except At)
I. Forms the weakest acid?
II. Has the largest atom?
III. Has the minimum ionization enthalpy?
IV. Has the maximum electron affinity?

3

(a)

What happens when SO₂ is passed through an aq. Solution of Fe (III) salt. Give equation.

3

(a)

On reaction with Cl₂, phosphorus forms two types of halides 'A' and 'B'.  Halide A is yellowish-white powder but halide 'B' is colourless oily liquid.  Identify A and B and write the formulas of their hydrolysis products.

3

(a)

P₄O₆ reacts with water according to equation P₄O₆ + 6H₂O \(\to\) 4H₃PO₃.  Calculate the volume of 0.1 M NaOH solution required to neutralise the acid formed by dissolving 1.1 g of P₄O₆ in H₂O.

3

(a)

White phosphorus reacts with chlorine and the product hydrolyses in the presence of water.  Calculate the mass of HCl obtained by the hydrolysis of the product formed by the reaction of 62g of white phosphorus with chlorine in the presence of water.

3

(a)

Phosphorus has three allotropic forms -     (i) white phosphorus     (ii) red phosphorus and     (iii) black phosphorus.  Write the difference between white and red phosphorus on the basis of their structure and reactivity.

3

(a)

An almorphous solid "A" burns in air to form a gas "B" Which turns lime water milky.  The gas is also produced as a by-product during roasting of sulphide ore.  This gas decolourises acidified aqueous KMnO₄ solution and reduces Fe³⁺ to Fe²⁺.  Identify the soild "A" and the gas "B" and write the reactions involved.

3

(a)