Q. Which of the following solutions will have pH close to 1.0?
A) $100\ mL\ of\frac{M}{10}\ HCl + 100\ mL\ of\ \frac{M}{10}\ NaOH$
B) $55\ mL\ of\frac{M}{10}\ HCl + 45\ mL\ of\ \frac{M}{10}\ NaOH$
C) $10\ mL\ of\frac{M}{10}\ HCl + 90\ mL\ of\ \frac{M}{10}\ NaOH$
D) $75\ mL\ of\frac{M}{5}\ HCl + 25\ mL\ of\ \frac{M}{5}\ NaOH$
Explanation
(d)
$N = \frac{75 \times \frac{1}{5} - 25 \times \frac{1}{5}}{100} = 15 - 5 = \frac{10}{100} = 0.1$
$pH = - \log{\left\lbrack H^{+} \right\rbrack = - \log{\lbrack 0.1\rbrack = 1}}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.