Which of the following statements is false?

1. ONCl and ${\mathrm{ONO}}^{- }$are isoelectronic.

2. ${\mathrm{O}}_3$ molecule is bent

3. Ozone is violet-black in solid-state

4. Ozone is diamagnetic gas

A chemical that depletes the ozone layer is:

1. Sulphur

2. Chlorofluorocarbons (CFCs)

3. Nitrogen

4. Hydrogen

Sulphuric acid is used:

The catalyst that is used in the contact process is:

The chemical formula of oleum is - 

A compound among the following that has an -O-O- linkage is:

1. ${\mathrm{H}}_2{\mathrm{SO}}_4$$,$ $\mathrm{sulphuric}$ $\mathrm{acid}$

2. ${\mathrm{H}}_2{\mathrm{S}}_2{\mathrm{O}}_8,$ $\mathrm{peroxodisulphuric}$ $\mathrm{acid}$

3. ${\mathrm{H}}_2{\mathrm{S}}_2{\mathrm{O}}_7,$ $\mathrm{pyrosulphuric}$ $\mathrm{acid}$

4. ${\mathrm{H}}_2{\mathrm{SO}}_3,$ $\mathrm{sulphurous}$ $\mathrm{acid}$

The acidity of diprotic acids in aqueous solution increases in the order:

1. H₂S < H₂Se < H₂Te

2. H₂Se < H₂S < H₂Te

3. H₂Te < H₂S < H₂Se

4. H₂Se < H₂Te < H₂S

Match the items in Columns I and II and mark the correct option.

Codes

Which of the following hydrides is the most acidic?

1. H₂Te

2. H₂Se

3. H₂O

4. H₂S

An amorphous solid“A” burns in the air to form a gas “B” which turns lime water milky. The gas is also produced as a by-product during the roasting of sulphide ore. This gas decolourises acidified aqueous KMnO₄ solution and reduces Fe³⁺ to Fe²⁺. The solid "A" and the gas "B" are:

1. 'A' = S₈: ‘B' = SO₂

2. 'A' = S₈: ‘B' = SO₃

3. 'A' = S₁₀: ‘B' = SO₂

4. Not predictable