Question

Q.35
An aqueous solution which is 20%(w/w) and 30% (w/v) in NaOH. What will be mass fraction of water
in 30 ml of such solution. ​

Answer 1

Answer:

mass fraction of water = 0.8

Step-by-step explanation:

20%(w/w) of NaOH :-   20 g NaOH in 100g solution

30%(w/v) of  NaOH :-  30gm in 100ml of Solution

W of NaOH in 30 mL solution  =  (30/100)*30 g = 9g

Vol. of solution for 20g NaOH = (100/30)*20 mL = 200/3 mL

now,

200/3 mL of solution = 100 g solution

=>30mL of solution  =  45 g solution

now, mass of water in 45g solution = (45-9)g  =  36g

Mass Fraction of Water = 36/45 = 0.8