Question

What will be the molarity of a solution containing 5 g of sodium hydroxide in 250 mL of water?

• A. 0.5 M
• B. 1.0 M
• C. 2.0 M
• D. 0.1 M

Answer 1

The correct option is A 0.5 M

molar mass of $NaOH$ = 40 g/mol
Number of moles = $\frac{5}{40}$ = 0.125 mol
Molarity M = $\frac{\text{number of moles}}{\text{Volume of the solution( mL)}}\times 1000$
M = $\frac{0.125}{250}\times 1000$ = 0.5 M