p-Block Elements (Group 15–18)

Roasting of sulphides gives the gas X as a byproduct. This is a colourless gas with choking smell of burnt sulphur and causes great damage to respiratory organs as a result of acid rain. Its aqueous solution is acidic, acts as a reducing agent and its acid has never been isolated. The gas X is

1. CO2
2. SO3
3. H2S
4. SO2

Identify the incorrect statement, regarding the molecule XeO4:

1. XeO4 molecule is square planar.
2. There are four p -d bonds.
3. There are four sp3-p, bonds.
4. XeO4 molecule is tetrahedral.

In which of the following arrangements the given sequence is not strictly according to the property indicated against it?

1. HF < HCl < HBr < HI : increasing acidic strength
2. H2O < H2S < H2Se < H2Te : increasing pKa values
3. NH3 < PH3 < AsH3 < SbH3 : increasing acidic character
4. CO2 < SiO2 < SnO2 < PbO2 : increasing oxidising power

Which of the following statements is not valid for oxoacids of phosphorus?

1. Orthophosphoric acid is used in the manufacture of triple superphosphate.
2. Hypophosphorous acid is a diprotic acid.
3. All oxoacids contain tetrahedral four coordinated phosphorus.
4. All oxoacids contain at least one P=O unit and one P-OH group.

Sulphur trioxide can be obtained by which of the following reactions?

1. CaSO4 + C
2. Fe2(SO4)3
3. S + H2SO4
4. H2SO4 + PCl5

How many bridging oxygen atoms are present in P4O10?

1. 6
2. 4
3. 2
4. 5

Match List-I (substances) with List-II (processes) employed in the manufacture of the substances and select the correct option.

1. (A) (i); (B) (iv); (C) (ii); (D) (iii)
2. (A) (i); (B) (ii); (C) (iii); (D) (iv)
3. (A) (iv); (B) (iii); (C) (ii); (D) (i)
4. (A) (iv); (B) (ii); (C) (iii); (D) (i)

Oxidation states of P in H4P2O5, H4P2O6, H4P2O7 are respectively

1. +3, +5, +4
2. +5, +3, +4
3. +5, +4, +3
4. +3, +4, +5

Among the following which is the strongest oxidising agent?

1. Br2
2. I2
3. Cl2
4. F2

Which of the following arrangements do not give the correct picture of the trends indicated against them?

1. F2 > Cl2 > Br2 > I2 : Bond dissociation energy
2. F2 > Cl2 > Br2 > I2 : Electronegativity
3. F2 > Cl2 > Br2 > I2 : Oxidizing power
4. F2 > Cl2 > Br2 > I2 : Electron gain enthalpy