JEE Main · 2021 · 01 Sep 2021 · Shift 2 · Some Basic Concepts of Chemistry

If 80 g of copper sulphate

CuSO_{4} \cdot 5 H_{2} O

is dissolved in deionised water to make 5 L of solution. The concentration of the copper sulphate solution is

x \times 1 0^{- 3} mol L^{- 1}

. The value of x is ____. [Atomic masses

Cu : 63.54 u, S : 32 u, O : 16 u, H : 1 u

]

Answer: 64

Solution

The molar mass of

CuS O_{4} \cdot 5 H_{2} O

63.54 + 32 + 4 (16) + 5 (18) = 249.54 g mo l^{- 1}

. Moles dissolved

= \frac{80}{249.54} = 0.3206 mol

. Concentration

= \frac{0.3206}{5} = 0.0641 mol L^{- 1} = 64.1 \times 1 0^{- 3} mol L^{- 1}

, so

x = 64

JEE Main · 2021 · 01 Sep 2021 · Shift 2 · Integer answer