Question

A saturated solution of sodium chloride is prepared at 373 K is using 100 kg of salt.

a. How much water is required? (Ans. 251.26 kg)

b. If the solution is cooled to 273 K, how much salt is precipitated out of the solution? (Ans. 10.3 kg)

Answer 1

Ans :

a)

The saturated solution of sodium chloride in water at 373 K has 39.8 g of NaCl in 100 g water.

So water required in the solution using 100 kg of salt will be :

= ( 100 x 100) / 39.8

= 251.26 kg

b)

The solution of sodium chloride in water at 273 K is 35.7 g/100 g water

So the amount of salt in 251.26 kg of water will be :

= (35.7 g x 251.26 kg) / 100 g

= 89.7 kg

Then the amount of salt precipitated out of solution = total salt - salt dissolved

= 100 kg - 89.7 kg

= 10.3 kg