Question

Identify X in the given reaction.
${\text{CH}}_3{\text{CH}}_2\text{OH}\text{(aq)}\stackrel{\text{X}}{\to }{\text{CH}}_2={\text{CH}}_2\text{(g)}+{\text{H}}_2\text{O(l)}$

• A. Alkaline ${\text{KMnO}}_4$
• B. Acidified ${\text{KMnO}}_4$
• C. Dilute ${\text{H}}_2{\text{SO}}_4$
• D. Concentrated ${\text{H}}_2{\text{SO}}_4$

Answer 1

The correct option is D Concentrated ${\text{H}}_2{\text{SO}}_4$

The given reaction is a dehydration reaction in which ethanol is when heated with concentrated sulphuric acid at 443 K gives ethene and water.
In this reaction, $\text{conc.}{\text{H}}_2{\text{SO}}_4$ is used because it is a strong dehydrating agent. The reaction occurs as follows:

${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}\left(\mathrm{aq}\right)\underset{}{\overset{\mathrm{Hot}\mathrm{conc}.H_2{\mathrm{SO}}_4}{\to }}{\mathrm{CH}}_2={\mathrm{CH}}_2\left(g\right)+H_{2}O\left(l\right)$

Therefore, X is concentrated sulphuric acid.