(a) Name an element which reacts with hydrogen to form a compound which is strongly acidic in water.
(a) Name an element which reacts with hydrogen to form a compound which is strongly acidic in water.
(b) Explain why to dilute hydrochloric acid cannot be concentrated by boiling beyond 22.2%.
1 Answers
(a) Chlorine.
The compound formed which is strongly acidic in water, is HCl.
H2 + Cl2 → 2HCl
(b) A dilute aqueous solution of hydrochloric acid gets gradually concentrated on distillation, till the concentration of the acid reaches 22.2% HCl by weight which boils at 110°C. When this concentration is reached, no further increase in concentration of the acid becomes possible by boiling. This is because vapors evolved before 110°C are vapors of water but at temperature above 110°C vapors consist mostly of molecules of HCl.