Question

3. Determine the pH at 25C of a solution prepared by dissolving 0.25 mole of ammonium chloride in 1.0 L of 0.28 M aqueous ammonia.

7.The pH of a bicarbonate-carbonic acid buffer is 7.28. Calculate the ratio of the concentration of carbonic acid (H₂CO₃) to that of the bicarbonate ion (HCO₃^−).(K_a1 of carbonic acid is 4.2 ×10^−7)

18. Calculate the pH of the following two buffer solutions:
(a) 1.1 M CH₃COONa/2.9 M CH₃COOH.
(b) 0.1 M CH₃COONa/0.3 M CH₃COOH.
Which is the more effective buffer?

A.	1.1 M CH3COONa/2.9 M CH3COOH
B.	0.1 M CH3COONa/0.3 M CH3COOH

32. The pH of a sodium acetate-acetic acid buffer is 4.60. Calculate the ratio [CH₃COO^−] / [CH₃COOH].