The solubility in mol dm−³ of 20g of CuSO4 dissolved in 100g of water at 180°C is [Cu = 64, S = 32, O =16]

A. 0.13
B. 0.25
C. 1.25
D. 2.00

Correct Answer:

Option C – 1.25

Explanation

Relative molecular mass of CuSO4 = 64 + 32 + 16 X 4 = 160
The number of moles of CUSO4 = reacting mass/molecular mass = 20/180 = 0.125
100g of water dissolved 0.125m of CuSO4
100g of water will dissolve (0.125 * 1000)/100 = 1.25mol dm³