Question

Give reasons for the following:
Dilute sulphuric acid is a stronger acid compared to concentrated sulphuric acid.

Answer 1

Acidity if a compound is determined by the number of protons or hydronium ions present. Concentrated sulphuric acid consists mostly of molecules of sulphuric acid, H₂SO₄, and very few dissociated ions.
When it is diluted with water, almost all of the sulphuric acid molecules dissolve in water and dissociate into ions. As there are more number of ions in diluted form than concentrated form, the dilute sulphuric acid is more acidic.

H₂SO₄(l) + H₂O(l)