Pehal and Ishaan were making 100 g sugar solutions with concentration by mass 20% and 50% respectively. Pehal added 20 g of sugar in her solution whereas Ishaan evaporated 20 g of water from his solution. Now, the two solutions were mixed to form a final solution. The concentration by mass of final solution is (1) 28% (2) 45% (3) 40% (4) 60%
Answers
Answer:The concentration by mass of final solution is 45% .
Solution
In case of Pehal, 20% of sugar solution in which she added 20 g of sugar more.
Mass of sugar before addition to the solution = 20 g
Mass of sugar after addition to the solution = 20 +20 = 40 g
Mass of water in solution= 80 g
= Total mass of solution= 80 g + 40 g = 120 g
In case of Ishaan, 50% of sugar solution from which he evaporated 20 g of water.
Mass of sugar in solution = 50 g
Mass of water before evaporation= 50 g
Mass of water after evaporation = 50 g - 20 g = 30 g
= Total mass of solution=50 g + 30 g = 80 g
After mixing both the solution
Total mass of sugar after the mixing of solutions,(M) = 40 g + 50 g = 90 g
Total mass of the final solution= =120 g + 80 g = 200 g
Mass percentage of sugar in final solution=
The concentration by mass of final solution is 45%
Pehal soultion-
Solute=20
Solvent=80
Solution=20+80=100
After adding,
Solute=20+20=40
Solvent=80
Solution=80+40=120
Ishaan Solution-
Solute=50
Solvent=50
Solution=100
After evaporating,
Solute=50
Solvent=50-20=30
Solution=50+30=80
Final solution,
Solute=50+40=90
Solvent=80+30=110
Solution=90+110=200
Percentage- 90×100/200=60%
Thank you