p-Block Elements (Group 15–18)

Which is the strongest acid in the following?

1. HClO4
2. H2SO3
3. H2SO4
4. HClO3

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