The pH of a solution changes from 3 to 6. The H+ ion concentration will
- Aincrease 3 times
- Bdecrease 3 times
- Cdecrease 10 times
- Ddecrease 1000 times
- ENone of the above / More than one of the above
Show answer and explanation
Correct answer: (d) decrease 1000 times
Explanation
pH = –log[H+], so at pH 3 the concentration is 10⁻³ and at pH 6 it is 10⁻⁶.
The ratio is 10⁻⁶ / 10⁻³ = 10⁻³, meaning [H+] falls by a factor of 1000.
Each unit rise in pH lowers [H+] ten-fold, so a 3-unit rise gives a 1000-fold decrease.