Question

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.

NCERT Class X
Science - Exemplar Problems

Chapter_Acids, Bases and Salts

Answer 1

Dry HCL gas=>Blue to Red
Moistened NH3 gas=>Red To Blue
Lemon Juice=>Blue To Red
Carbonated soft drink=> Blue To Red
Curd=>Blue To Red
Soap Solution => Red To Blue

Answer 2

• Turn RED in case of HCl as it contains ACIDIC ions.
• Turns into BLUE colour as Ammonia is a BASE.
• turns to RED as it is a mild or weak ACID.
• It is slightly ACIDIC and will thus turn to RED colour.
• Curd contains Lactic Acid in it which is ACIDIC in nature and thus turns to RED.
• Soap solution contains Sodium Hydroxide which is a BASE and thus it turns to BLUE colour.

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