Given:
pH = 4.2 of tomato
Required:
hydrogen-ion concentration [H+]| for tomato juice
Solution:
The formula for the pH relating hydrogen ion concentration is pH = -log[H+] where H+ is the hydrogen ion concentration. so, substitute the value of pH
pH = -log[H+]
4 = - log[H+]
-4 = log[H+]
10^-4 = [H+]
[H+] = 1x10^-4M