Question

On passing electricity, acidulated water gives oxygen and hydrogen. Oxygen formed, on treatment with carbon monoxide forms carbon dioxide, which on dissolution in water forms the corresponding acid. The acid formed on treatment with sodium hydroxide gives the corresponding salt and water. The aqueous solution of salt is then treated with potassium. Various types of reactions involved in the above process are given below. Arrange them in a proper sequence as given above.

(a) Double displacement

(b) Displacement

(c) Decomposition

(d) Combination

• A. dcba
• B. cdab
• C. cdba
• D. dcab

Answer 1

The correct option is B

cdab

Explanation for the correct option:

• On passing electricity, acidulated Water ($H_{2}O$) gives Oxygen ($O$) and Hydrogen ($H$). The reaction is given below:

$\underset{\mathrm{Water}}{2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}\to \underset{\mathrm{Hydrogen}}{2{\mathrm{H}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{Oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}$

This reaction is Decomposition reaction because Water is decomposing into Hydrogen and Oxygen.

• Oxygen formed, on treatment with Carbon monoxide ($CO$) forms Carbon dioxide ($C{O}_2$), which on dissolution in water forms the corresponding acid. The reactions are given below:

$\underset{\mathrm{Oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{Carbon}\mathrm{monoxide}}{2\mathrm{CO}\left(\mathrm{g}\right)}\to \underset{\mathrm{Carbon}\mathrm{dioxide}}{2{\mathrm{CO}}_2\left(\mathrm{g}\right)}$

• Carbon dioxide on reaction with Water forms Carbonic acid ($H_{2}C{O}_3$). The reaction is given below:

$\underset{\mathrm{Carbon}\mathrm{dioxide}}{{\mathrm{CO}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}\to \underset{\mathrm{Carbonic}\mathrm{acid}}{{\mathrm{H}}_2{\mathrm{CO}}_3\left(\mathrm{aq}\right)}$

Both the above reactions are Combination reaction because two reactants are forming one product.

• The acid formed on treatment with Sodium hydroxide ($NaOH$) gives the corresponding salt and water. The salt formed will be Sodium bicarbonate ($NaHC{O}_3$) and Water. The reaction is given below:

$\underset{\mathrm{Carbonic}\mathrm{acid}}{{\mathrm{H}}_2{\mathrm{CO}}_3\left(\mathrm{aq}\right)}+\underset{\mathrm{Sodium}\mathrm{hydroxide}}{\mathrm{NaOH}\left(\mathrm{aq}\right)}\to \underset{\mathrm{Sodium}\mathrm{bicarbonate}}{{\mathrm{NaHCO}}_3\left(\mathrm{aq}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{aq}\right)}$

This is a Double displacement reaction.

• The aqueous solution of salt is then treated with Potassium ($K^{+}$). The reaction is given below:

$\underset{\mathrm{Sodium}\mathrm{bicarbonate}}{{\mathrm{NaHCO}}_3\left(\mathrm{aq}\right)}+\underset{\mathrm{Potassium}}{{\mathrm{K}}^{+}\left(\mathrm{aq}\right)}\to \underset{\mathrm{Potassium}\mathrm{bicarbonate}}{{\mathrm{KHCO}}_3\left(\mathrm{aq}\right)}+\underset{\mathrm{Sodium}}{{\mathrm{Na}}^{+}\left(\mathrm{aq}\right)}$

The is Displacement reaction.

The series will be Decomposition reaction, Combination reaction, Double displacement reaction and Displacement reaction, so the order will be cdab.

Therefore, the correct option is (B).