Question

Metal oxide, sulphur dioxide and oxygen are formed on the decomposition of

• A. metal carbonates
• B. metal sulphates
• C. metal nitrates
• D. metal chlorides

Answer 1

The correct option is B

metal sulphates

Explanation for the correct option:

(b) On decomposition, metal sulphates yield Metal oxide, Sulphur dioxide and Sulphur trioxide.

• Sulphur trioxide decomposes further decomposes to Sulphur and oxygen gas.

$\underset{(\mathrm{Ferrous}\mathrm{sulphate})}{2{\mathrm{FeSO}}_4\left(\mathrm{s}\right)}\stackrel{\mathrm{Heat}}{\to }\underset{(\mathrm{Ferric}\mathrm{oxide})}{{\mathrm{Fe}}_2{\mathrm{O}}_3\left(\mathrm{s}\right)}+\underset{(\mathrm{Sulphur}\mathrm{dioxide})}{{\mathrm{SO}}_2\left(\mathrm{g}\right)}+\underset{(\mathrm{Sulphur}\mathrm{trioxide})}{{\mathrm{SO}}_3\left(\mathrm{g}\right)}$

Explanation for the incorrect options:

(a) On decomposition, metal carbonates yield Metal oxide and Carbon dioxide (CO₂).

$\underset{(\mathrm{Calcium}\mathrm{carbonate})}{{\mathrm{CaCO}}_3\left(\mathrm{s}\right)}\stackrel{\mathrm{Heat}}{\to }\underset{(\mathrm{Calcium}\mathrm{oxide})}{\mathrm{CaO}\left(\mathrm{s}\right)}+\underset{(\mathrm{Carbon}\mathrm{dioxide})}{{\mathrm{CO}}_2\left(\mathrm{g}\right)}$

(c) On decomposition, metal chlorides yield Metal and Chlorine (Cl₂) gas.

$\underset{(\mathrm{Silver}\mathrm{chloride})}{2\mathrm{AgCl}\left(\mathrm{s}\right)}\underset{\left(\mathrm{Silver}\right)}{\stackrel{\mathrm{Sunlight}}{\to }2\mathrm{Ag}\left(\mathrm{s}\right)}+\underset{\left(\mathrm{Chlorine}\right)}{{\mathrm{Cl}}_2\left(\mathrm{g}\right)}$

(d) On decomposition, metal nitrates yield Metal oxide, Nitrogen dioxide (NO₂) and Oxygen gas (O₂).

$\underset{(\mathrm{Lead}\mathrm{nitrate})}{2\mathrm{Pb}{\left({\mathrm{NO}}_3\right)}_2\left(\mathrm{s}\right)}\stackrel{\mathrm{Heat}}{\to }\underset{(\mathrm{Lead}\mathrm{oxide})}{\mathrm{PbO}\left(\mathrm{s}\right)}+\underset{(\mathrm{Nitrogen}\mathrm{dioxide})}{4{\mathrm{NO}}_2\left(\mathrm{g}\right)}+\underset{\left(\mathrm{Oxygen}\right)}{{\mathrm{O}}_2\left(\mathrm{g}\right)}$

Therefore, option (b) is correct.