Question 4 of 171

The Ksp (25°C) of sparingly soluble salt XY2(s) is 3.56X10-5(mol lit-1)3 and at 30°C the vapour presence of its saturated solution in water is 31.78 mm Hg. Calculate the enthalpy change of the reaction.

XY2(s)          X2+(aq) + 2Y-(aq)

Given: Vapour pressure of pure water=31.82 mm Hg

(a) 42.5 kJ/mol.

(b) 32.1 kJ/mol.

(c) 24.5 kJ/mol.

(d) 52.5 kJ/mol.