Question

What happens when dilute solution of sodium hydroxide is mixed with a dilute solution of hydrochloric acid and the resultant solution is tested with blue and red litmus paper ? Explain with the help of an equation ?​

Answer 1

NaCl and H₂O is formed as products. No change in colours of blue and red litmus paper.

EXPLANATION

• We are required to explain what happens when dilute Sodium hydroxide is mixed with hydrochloric acid.
• When NaOH and dil HCl are mixed together, Nacl (Sodium chloride) is formed along with water as a by-product.
• The reaction is depicted as under;

dil NaOH + dil HCl --------> NaCl + H₂O

• Such reaction in which acid and base reacts to form a salt is known as neutralization reaction.
• The reaction is called so because there are no excess hydrogen or hydroxyl ions present in the solution.
• No change occurs when the resultant solution is tested with blue or red litmus paper as the NaCl solution is neutral.
• The pH of NaCl solution is 7.

#SPJ1

Answer 2

A mixture containing dilute solution of sodium hydroxide (NaOH)  and dilute solution of hydrochloric acid (HCl) yields sodium chloride (NaCl) and water.

When dilute NaOH is mixed with dilute HCl:

dil. NaOH + dil. HCl → NaCl + H₂O

This is a neutralization reaction.

Litmus paper: Litmus paper is a filter paper, used as a pH indicator.

Litmus paper is used to identify whether a solution is acidic or basic.

Blue litmus paper turns red in acidic solution and red litmus turns blue in a basic solution.

Sodium chloride is a salt and has a pH=7(neutral), not an acid or a base, therefore on testing the resulting solution with blue and red litmus paper, no color change is seen.

Hence, the resultant solution will show no change in color when tested with blue and red litmus paper.

#SPJ1