Question

The pH of the solution produced when an aqueous solution of strong acid pH 5 is mixed with equal volume of an aqueous solution of a strong acid of pH 3 is:

• A. 3.3
• B. 3.5
• C. 4.5
• D. 4

Answer 1

The correct option is A 3.3

Concentration produced by solution of pH 5 = 0.00001 mol/ L

Concentration produced by solution of pH 3 = 0.001 mol/ L

Concentration of $H^{+}$ ion of resultant solution $=$(Concentration of $H^{+}$ ion produced by solution of pH 5 + Concentration of $H^{+}$ ion produced by solution of pH 3)/(2)

$H^{+}=$ 0.00001 + $\frac{0.001}{2}$ mole

$=$ 0.000505 mol/lt

$pH=-lo{g}_{10}\left[H^{+}\right]$

$pH=-lo{g}_{10}\left(0.000505\right)$

$pH=3.3$