Concentration of a solution

• A binary solution has two components or constituents. The relative amounts of solute and solvent in the solution either by mass or by volume represent the concentration of the solution.
• Based upon these, solutions are of different types like dilute, concentrated, saturated and unsaturated.
• The solution having small amount of solute is said to have low concentration. It is known as a dilute solution.
• The solution having a large amount of solute is said to be of high concentration.
• Concentration of solution is normally expressed as mass percent or volume percent.

Mass percent:

• Mass percent of a solution is the number of parts by mass of one component (solute or solvent) per 100 parts by mass of the solution.

If A and B are the two components of a binary solution-

Volume Percent:

• Volume percent of a solution is the number of parts by volume of one component (solute or solvent) per 100 parts by volume of solution.

Question 1

Calculate the masses of cane sugar and water required to prepare 250 g of 25% solution of cane sugar.

Ans:

Mass percent =

Mass percent = 25, Mass of solution = 250 g

∴ 25 =

∴ Mass of cane sugar =

Mass of water = 250 – 62.5 = 187.5 g

Question 2

A solution has been prepared by dissolving 5 g of urea in 95 g of water. What is the mass percent of solution in water?

Ans:

Mass percent (Mass %) =

Mass of urea = 5 g, Mass of water = 95 g

Mass percent of urea =

Question 3

A solution contains 5 mL of alcohol mixed with 75 mL of water. Calculate the concentration of this solution in terms of volume percent.

Ans:

Concentration of solution =

Volume of alcohol = 5 mL

Volume of solution = (5 + 75) = 80 mL

Concentration of solution =

Question 4

A solution contains 35 g of common salt in 300 g of water. Calculate the concentration of the solution.

Ans:

Concentration of solution =

Mass of common salt = 35g

Mass of water = 300 g

Mass of solution = (300 + 35) = 335g

Concentration of solution = .