Question

(a) What is produced if an acid is added to a base ?
(b) Why does dry HCl gas not change the colour of dry litmus paper ?
(c) What colour does phenolphthalein indicator turn when added to an alkali (such as sodium hydroxide) ?

Lakhmir Singh Chemistry Class 10

Answer 1

a) when acid and base mix with each other they form water and salt

Answer 2

Answer:

(b)In this HCL is not aqueous form nor litmus paper is wet, so the colour of litmus paper does not change.

Explanation:

We know that the colour of litmus paper is changed by H+ ions because of acid. Dry HCL does not dissociate to give H+ ions.