Question

how does the pH value of rain drop to 5.6 causing an acid rain?

Answer 1

Dear student!

The value pH = 7 is known as the neutral point of pH scale above which the pH values like 8,9 etc show basic characters while the pH values below 7 i.e. 6,5 , 4 etc are known to have acidic nature.

Since, the rain water has a pH value of 5.6, so it is considered to be acidic.

Actually, the pH value is the concentration of H⁺ ion so that, pH = -log [H⁺]

so, smaller the -ve logarithm of hydrogen ion, larger is the strength of hydrogen ion concentration and so more acidic will be the compound.