If 80 g of copper sulphate CuSO4 . 5H2O is dissolved in deionised water to make 5L of solution. The concentration of the copper sulphate solution is x ×10−3 mol L−1. The value of x is _____________.(nearest whole number)[Atomic masses Cu : 63.54u, S : 32u, O : 16u, H : 1u]

Given, mass of CuSO4 . 5H2O = 80 gThe concentration of copper sulphate solution is  x×10-3mol/L  Molarity = Number of moles of soluteVolume of solution(L) ..... (i)Molar mass of CuSO4 . 5H2O = 63.54 + 32 + 16 × 4                                    = 5 × 18 = 249.54 g/molNumber of moles of solute = Weight of soluteMolecular mass of solute                            = 80g249.54g/mol = 0.32 molVolume of solution = 5 LFrom Eq. (i),Molarity = 0.32055 = 64.11×10−3 mol/L∴ x = 64.11or x ≈ 64Hence, answer is 64.