Question

The molarity of sodium hydroxide in the solution prepared by dissolving 6 g in 600 mL of water is (molar mass of NaOH = 40 g mol\(^{-1}\)):

• A. 0.5 M
• B. 0.4 M
• C. 0.25 M
• D. 0.1 M
• E. 0.2 M

Hint:

Molarity is calculated by dividing the number of moles of solute by the total volume of the solution in liters.

Answer 1

The Correct Option is C

Molarity (\( M \)) is calculated using the formula: \[ M = \frac{{\text{moles of solute}}}{{\text{volume of solution in liters}}} \] First, determine the moles of NaOH: \[ \text{Moles of NaOH} = \frac{{\text{mass}}}{{\text{molar mass}}} = \frac{6\, \text{g}}{40\, \text{g/mol}} = 0.15\, \text{mol} \] The volume of the solution is 600 mL, which is 0.6 L. Substituting the values: \[ M = \frac{0.15}{0.6} = 0.25 \, M \] Thus, the molarity of the solution is 0.25 M.