Question

The molar solubility (in mol L–1) of a sparingly soluble salt MX4 is s. The corresponding solubility product is Ksp.. s is given in terms of Ksp by the relation

• A. s = (Ksp/128)1/4
• B. s = (128Ksp)1/4
• C. s = (256Ksp)1/5
• D. s = (Ksp/256)1/5

Answer 1

Answer: (D)

s = (Ksp/256)1/5

Answer 2

MX4 (solid) $\rightleftharpoons$ $\mathrm { M } ^ { 4 + } { } _ { ( \mathrm { aq } ) } + 4 \mathrm { X } _ { ( \mathrm { aq } ) } ^ { - }$ Solubility product, Ksp = s × (4s)4 = 256 s5

$\therefore$ s = $\left( \frac { \mathrm { K } _ { \mathrm { ps } } } { 256 } \right) ^ { 1 / 5 }$