Question

Let's suppose you have four solutions of salt water. Solution 1 has 55 g of salt dissolved in 445 mL of water. Solution 2 has a concentration of 21 %. Solution 3 has 36 g of salt dissolved in 108 mL of water. Solution 4 has a concentration of 23 %. Which of the following lists the solutions in order from the least concentrated to the most concentrated?

• A. 1, 2, 3, 4
• B. 1, 2, 4, 3
• C. 2, 4, 3, 1
• D. 3, 4, 2, 1

Answer 1

The correct option is B

1, 2, 4, 3

The concentration (mass percentage) of a solution can be calculated from the given formula -

$Concentration=\frac{massofthesolute}{massofthesolution}\times 100\%$

Please note that 1 mL of water has a mass of 1 g. Also, Mass of solution = mass of solute + mass of solvent

So, concentration of solution 1 = $\frac{55}{445+55}\times 100\%=\frac{55}{500}\times 100\%=11\%$

Also, concentration of solution 3 = $\frac{36}{108+36}\times 100\%=\frac{36}{144}\times 100\%=25\%$

We already have the concentrations of solution 2 and 4.

A solution with high concentration has more amount of solute dissolved as compared to a solution with less concentration in the same amount of solvent.

So, on arranging the solutions in order from the least concentrated to the most concentrated we get:

1 < 2 < 4< 3