Question 12 Marks
What will be the action of the following substances on litmus paper?
i. Dry HCl gas
ii. Moistened $\mathrm{NH}_{3}$ gas
iii. Curd
iv. Soap solution.
i. Dry HCl gas
ii. Moistened $\mathrm{NH}_{3}$ gas
iii. Curd
iv. Soap solution.
Answer
View full question & answer→i. No change in colour will be seen as dry HCl will not liberate $\mathrm{H}^{+}$ions.
ii. It will turn red litmus paper to blue because moistened $\mathrm{NH}_{3}$ gas will form Ammonium Hydroxide $\left(\mathrm{NH}_{4} \mathrm{OH}\right)$.
iii. Curd will turn blue litmus paper into the red as it contains lactic acid.
iv. Soap solution will turn red litmus paper to blue as it is basic in nature.
ii. It will turn red litmus paper to blue because moistened $\mathrm{NH}_{3}$ gas will form Ammonium Hydroxide $\left(\mathrm{NH}_{4} \mathrm{OH}\right)$.
iii. Curd will turn blue litmus paper into the red as it contains lactic acid.
iv. Soap solution will turn red litmus paper to blue as it is basic in nature.