Question

Calculate Molarity of a solution having 3.42 gm sucrose in 500 mL - solution.

• A. 0.2 M
• B. 0.02 M
• C. 2 M
• D. 0.342 M

Answer 1

The correct option is B

0.02 M

We know that,
Molarity=$\frac{\text{No. of moles of solute}}{\text{No of litres of solution}}$
We know the given weight of sucrose from which the number of moles of sucrose can be calculated. Therefore No. of moles =$\frac{Givenweight}{Molecularweight}$(solute is sucrose)
$=\frac{3.42}{342}=0.01$
When 0.01 moles of sucrose is added to 500ml
$\Rightarrow Molarity=0.01\times \frac{1}{500\times {10}^{-3}}(1mL={10}^{-3}L)$
$\Rightarrow$ Molarity = 0.02 M