Question

10 mL of ${10}^{6}MHCl$ solution is mixed with $90mL{H}_{2}O$.pH will change approximately

• A. by 1 unit
• B. by 0.3 unit
• C. by 0.7 unit
• D. by 0.1 unit

Answer 1

The correct option is C by 0.7 unit

Initial pH of HCl = 6
After mixing HCl and water:
$\left[H^{+}\right]fromHCl={10}^{-7}$
$\left[H^{+}\right]from{H}_{2}O={10}^{-7}$
$Total\left[H^{+}\right]=2\times {10}^{-7}$
$pH=6.7$