Question

Hydrogen ion concentration in mol/L in a solution of pH = 5.4 will be :

• A. $3.98 \times 10^{-6}$
• B. $3.68 \times 10^{-6}$
• C. $3.88 \times 10^{6}$
• D. $3.98 \times 10^{8}$

Answer 1

Answer: (A)

$pH =5.4$
$\therefore \quad\left[H^{+}\right]\approx 10^{-5.4} = 10^{-6}\cdot10^{0.6}$
Antilog of $0.6$ is $\approx 4$
$\therefore \quad\quad\left[H^{+}\right]\approx 4\times 10^{-6} \,M$