Question

The figure given below represents the experiment carried out between conc. sulphuric acid and sodium chloride, which react with each other to form HCl gas. Blue litmus paper is brought near the mouth of the delivery tube to check the presence of HCl acid but no change is observed in the colour of litmus paper because: 1]The litmus paper used is moist
2]The litmus paper used is dry
3]Blue litmus paper does not change its color with an acid
4]The litmus paper is kept very close to the mouth of the delivery tube

Answer 1

Answer:

2]the litmus paper used was dry

Explanation:

HCl gas being a covalent molecule does not ionise in a purely dry state. If the litmus paper was moist, then the water would ionise the HCl molecules releasing H+ ion which will change the colour of the indicator.

Answer 2

Answer:

the litmus paper used was dry