question_answer 51)

  What will be the action of the following substances on litmus paper? Dry HCl gas, moistened NH3 gas, lemon juice, carbonated soft drink, curd, soap solution.

Answer:

  (i) Dry HCl gas No change on litmus paper (ii) Moistened NH3 gas (basic) Red litmus will turn blue. (iii) Lemon Juice (contains citric acid) Blue litmus will turn red. (iv) Carbonated soft drinks (contains carbonic acid) Blue litmus will turn red. (v) Curd (contains lactic acid) Blue litmus will turn red. (vi) Soap solution (basic) Red litmus will turn blue.