Concentrated sodium hydroxide is 19.4 M and has a density of 1.54 g/mL.What is the molality of concentrated NaOH?
A) 12.6 m
B) 19.8 m
C) 25.4 m
D) 29.9 m
E) 50.4 m

Question

Quizplus · Accepted Answer

To find molality, we need the moles of solute per kilogram of solvent. First, calculate the mass of 1 L of solution using density: 1.54 g/mL * 1000 mL = 1540 g. The moles of NaOH in 1 L is 19.4 moles. The mass of NaOH is 19.4 moles * 40 g/mol = 776 g. The mass of water (solvent) is 1540 g - 776 g = 764 g = 0.764 kg. Molality = 19.4 moles / 0.764 kg = 25.4 m.

Concentrated Sodium Hydroxide Is 19