Question

What is the meaning of 10% solution of NaCl?

• A. 10 g NaCl in 100 grams of solution
• B. 58.5 grams of NaCl in 100 grams of solution
• C. 94 grams of NaCl in 100 grams of solution
• D. 5.85 grams of H2O in 100 grams of solution

Answer 1

Answer: (A)

A 10% (w/w) solution means that 10 grams of the solute (NaCl) are present in 100 grams of the total solution.

Answer 2

The notation "(w/w)" stands for weight/weight or mass/mass. A percentage concentration expressed as (w/w) is defined as:

$$\text{Percentage by weight (or mass)} = \frac{\text{Mass of solute}}{\text{Mass of solution}} \times 100\%$$

In this question, the solute is NaCl and the concentration is given as 10% (w/w). This means that 10 grams of solute (NaCl) are present in 100 grams of the solution.