Question

student dissolves 1 g of sodium hydroxide, NaOH, in a 250 cm3 volumetric flask. Calculate the concentration of the solution in mol dm–3.

Answer 1

Answer:

Molar mass of sodium = 23 g

Molar mass of oxygen = 16 g

Molar mass of hydrogen = 1g

Molecular mass of NaOH = 40g

No of moles of 1g NaOH = 1/40 = 0.025 moles

Volume of Soln = 250 cm^3 = 0.25 dm^3

[ 1cm^3 = 0.001 dm^3]

Molarity = no of moles / vol of Soln

= 0.025 / 0.25

= 0.1 mol dm^-3