Question

Calculate the molarity of NaOH in the solution prepared by dissolving its 4 g in enough water to form 250 mL of the solution.

Answer 1

Mass of NaOH = 4 g

Volume of solution = 250 mL = 0.250 L

Molar mass of NaOH = 23 + 16 + 1 = 40

Molarity (M) = ?

Molarity = \(\frac{No.\,of\,moles\,of\,solute}{volume\,of\,solution\,in\,litres}\)

= \(\frac{Mass\,of\,NaOH/Molar\,mass\,of\,NaOH}{volume\,of\,solution\,in\,liters}\)

= \(\frac{\frac{4\,g}{40\,g}}{0.250\,L}\)

= \(\frac{0.1\,mol}{0.250\,L}\)

= 0.4 M