Question

Take water in a test tube add a few drops of litmus to it. With the help of a straw, blow air into the solution. It turns red. Explain the reason behind the colour change. Please answer fast !!!!!!!!

Answer 1

We know that litmus turns red when in contact with an acidic fluid and it turns blue when in contact with a basic fluid.

Now, when we blow air into the solution the Carbon dioxide (CO2) present in air exhaled turns the litmus solution red. Since Carbon dioxide is acidic in nature, pH 6.

Answer 2

As we know exhaled air has carbon dioxide which when reacts to water , it forms carbonic acid and the bits of blue litmus turn red