Solutions, Suspensions and Colloids MCQs

Q1. While pickling vegetables a cook stirs 15 g of common salt into 135 g of warm water. What percentage by mass of the solution is the dissolved substance?

• A.90%
• B.15%
• C.10%
• D.11.1111%

Answer: C. 10%

Mass of solution = 15 + 135 = 150 g. Mass % of solute = (solute/solution) x 100 = (15/150) x 100 = 10%.

Q2. A gardener blends 40 g of urea into 160 g of water for a leaf spray. By mass, what percent of the final solution is made up of the solute?

• A.20%
• B.40%
• C.25%
• D.80%

Answer: A. 20%

Mass of solution = 40 + 160 = 200 g. Mass % of solute = (solute/solution) x 100 = (40/200) x 100 = 20%.

Q3. A nurse dissolves 9 g of boric acid in 141 g of water to make a wash. What is the mass percentage of solute (mass by mass) in the solution?

• A.6%
• B.94%
• C.6.383%
• D.9%

Answer: A. 6%

Mass of solution = 9 + 141 = 150 g. Mass % of solute = (solute/solution) x 100 = (9/150) x 100 = 6%.