Plz solve 6th ques.
Q.6. On adding 'x' g of the solute to 100 g aqueous solution, the concentration in terms of mass by mass percentage changes from 50 % to 60 %. Amount of solute 'x' is
(1) 20 g
(2) 10 g
(3) 35 g
(4) 25 g

The initial mass of the solution was 100g
As 50% (w/w) was present in 100g solution we can say the mass of the solute in initial solution was 50g
After addition of x g solute in 100g solution the changed mass of solution became (x+100)g and total amount of solute became (x+50)g.
So the percentage of solute in final solution became 60%.
So

(x+50)/(x+100)xx100=60
x+50)/(x+100)=60/100=0.6
x+50=0.6(x+100
x+50=0.6x+60
x-0.6x=60-50
0.4x=10
x=10/0.4=25