Question

1. Calculate the pH (to two decimal places) of a 2.69×10-2 M solution of hydrocyanic acid. If the 5% approximation is valid, use the assumption to compute pH.

2. Determine the pH (to 2 decimal places) of a 7.33×10^-1 M solution of sodium sulfite. If the 5% approximation is valid, use the assumption to compute pH.

3. The pH of a 7.41×10^-3 M solution of a weak base is 7.84. Calculate K_b for this base to three significant figures.