Question

Equal volumes of two solutions A and B of a strong acid having pH = 6.0 and pH = 4.0 respectively are mixed together to form a new solution. The pH of the new solution will be in the range:

• A. Between 5 and 6
• B. Between 6 and 7
• C. Between 4 and 5
• D. Between 3 and 4

Hint:

Key Points: For strong acids: pH = $-\log[\text{H^+]$ When mixing solutions: concentrations average (for equal volumes) The more acidic solution dominates the final pH pH calculation: $-\log(0.5 \times 10^{-4) = 4 - \log(0.5) \approx 4.3$