The solubility in moldm\(^{-3}\) of 20g of CuSO\(_4\) dissolved in 100g of water at 180\(^o\)C is
[Cu = 64, S = 32, O =16]
- 0.13
- 0.25
-
1.25
- 2.00
The correct answer is: C
Explanation
Relative molecular mass of CuSO4 = 64 + 32 + (16 x 4) = 160
The number of moles of CuSO\(_4\) = \(\frac{reacting mass}{molecular mass}\) = \(\frac{20}{160}\) = 0.125 mole
100g of water dissolved 0.125mole of CuSO\(_4\)
100g of water will dissolve (0.125 X 1000)/100 = 1.25 moldm\(^{-3}\)
Alternatively,
Solubility = Number of moles of solute x \(\frac{1000}{Volume of solvent}\)
But Number of moles of solute = \(\frac{mass}{molar mass}\) = \(\frac{20}{160}\) = 0.125 moles
Solubility = Number of moles of solute x \(\frac{1000}{Volume of solvent}\)
Solubility = 0.125 x \(\frac{1000}{100}\) = 1.25 moldm\(^{-3}\)