Question

a litmus paper was droped into 2ml dilute hcl. then 2ml concentrated naoh was added to it and stirred

Answer 1

The red damp litmus paper turns blue on contact with the NH3(g) formed from the reaction.

Answer 2

Blue litmus paper: HCl is Hydrochloric acid, so the blue litmus turns red. When equal amount of NaOH is added the colour again changes to blue and remains the same.

Red litmus paper: Red litmus paper shows no colour in hydrochloric acid. When some amount of NaOH is added the colour changes to blue initially but when the amount of NaOH is sufficient the blue colour disappears.

Equal amounts of HCl and NaOH results in the formation of NaCl, as salt, and the solvent water. This reaction is called the neutralization reaction.

NaOH+ HCl → NaCl+ H2O.

Base + Acid → Salt + Water.