Question

Calculate the molal concentration of a solution of NaCl which has a boiling point of
100.65°C.

Answer 1

Given problem is based on the colligative property , elevation in boiling point.

∆T = i × kb × m

m is molal concentration.

∆ T = elevation in boiling point

For water boiling point is 100 °c at 1 atm.

Given boiling point of solution = 100.65°c

∆T = 100.65 - 100 = 0.65 °C

For NaCl value of i = 2

For water Kb = 0.512 °C / molal

Now ,

m = ∆T ÷ ( i × kb )

m = 0.65 °C ÷ ( 2 × 0.512 °C/molal) = 0.6347 molal.

Molal concentration of given Solution of NaCl is 0.6347 molal .

answered by: anonymous