A₃B₂ is a sparingly soluble salt of molar mass M (g mol^$$-$$1) and solubility x g L^$$-$$1. The solubility product satisfies $${K_{sp}} = a{\left( {{x \over M}} \right)^5}$$. The value of a is _____________. (Integer answer)

The solubility of CdSO₄ in water is 8.0 $$\times$$ 10^$$-$$4 mol L^$$-$$1. Its solubility in 0.01 M H₂SO₄ solution is __________ $$\times$$ 10^$$-$$6 mol L^$$-$$1. (Round off to the Nearest Integer). (Assume that solubility is much less than 0.01 M)

In order to prepare a buffer solution of pH 5.74, sodium acetate is added to acetic acid. If the concentration of acetic acid in the buffer is 1.0 M, the concentration of sodium acetate in the buffer is ___________ M. (Round off to the Nearest Integer). [Given : pKa (acetic acid) = 4.74]

Sulphurous acid (H₂SO₃) has Ka₁ = 1.7 $$\times$$ 10^$$-$$2 and Ka₂ = 6.4 $$\times$$ 10^$$-$$8. The pH of 0.588 M H₂SO₃ is __________. (Round off to the Nearest Integer).