Question

State the reason for exhibiting acidic character by dry $\mathrm{HCl}$gas / $\mathrm{HCl}$solution.

Answer 1

Reason for exhibiting acidic character by dry $\mathrm{HCl}$gas / $\mathrm{HCl}$solution:

• Between dry $\mathrm{HCl}$ gas and $\mathrm{HCl}$ solution, acidic properties will be shown only by $\mathrm{HCl}$ solution.
• Dry gas does not show any effect on the pH paper or the litmus paper as it does not dissociate into ${\mathrm{H}}^{+}$ ions which is responsible for the acidic property.
• However, in presence of water $\mathrm{HCl}$dissociates into ${\mathrm{H}}^{+}$ions. Therefore, if we pass dry gas on moist litmus paper it will change to red color. Similarly, the solution of $\mathrm{HCl}$ also exhibits acidic properties.