Question

The density of 3 M solution of NaCl is 1.25 g mL-1. Calculate molality of the solution.
NCERT Class XII
Chemistry - Main Course Book I
Chapter 1. Some Basic Conpepts of Chemistry

Answer 1

HEYA!!
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▶Molecular Mass of NaCl :- 23 + 35.5

= 58.5

⏪Total Mass : 58.5× 3 = 175.5 g

Density = Mass/Volume

Mass = 1000g
Density = 1.25

Volume = 1.25 × 1000 = 1250 .

Volume of Solution = 1250 - 175.5

= 1074.5

Molality = 3 / 1074.5 × 1000

=2.79 Molal.

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