Question

Calculate the molarity (M) of a solution in which 2 mole of NaCl is dissolved in 5 litre of a solution.

• A. 1 M
• B. 1.5 M
• C. 0.4 M
• D. 2 M

Answer 1

The correct option is C 0.4 M

Given, the volume of the aqueous solution = 5 L
Number of moles of solute = 2 mol

Molarity of a solution is given by the formula
= $\frac{\text{Number of moles of solute}}{\text{Volume of the solution (litres)}}$ ....(i)
Putting the values of the volume of the solution and number of moles of a solute in equation (i) we have:
Molarity of a solution = $\frac{2}{5}=0.4$
Therefore the 2 moles of NaCl dissolved in 5 L of water will give 0.4 M solution.