Question

1. Assuming a negligible change in volume, how many moles of H3O+ or OH– must you add per litre to an acidic solution to adjust its pH from 5.80 to 6.25?

(A) 1.58 x 10–6 mol H3O+

(B) 2.14 x 10–6 mol OH–

(C) 1.02 x 10–6 mol H3O+

(D) 1.02 x 10–6 mol OH–

(E) 2.14 x 10–4 mol H3O+

2.. A buffer is prepared by mixing 100.0 mL of a 0.100 mol L–1 CH3COOH solution with a 0.200 mol L–1 solution of CH3COONa and making the total volume up to 1.000 L of water. What is volume of the CH3COONa solution required to achieve a buffer of pH = 4.5?

(Ka of CH3COOH = 1.8 x 10^-5)

Answer 1