Question

The molecular mass of sodium hydroxide is 40. If 1 litre of sodium hydroxide solution is prepared by dissolving 12 g of it then the molarity of the solution will be:

• A. 3 M
• B. 0.3 M
• C. 3.33 M
• D. 0.003 M

Answer 1

The correct option is B

0.3 M

Mass of sodium hydroxide (NaOH) taken = 12 g
Molar mass of NaOH = 40 g.

Number of moles of NaOH = $\frac{12}{40}=0.3$

Volume of solution = 1 l

$\therefore$ Concentration $=\frac{0.3}{1}=0.3M$