Question
250 mL of a NaCl solution contains 29 g of NaCl dissolved in water. Express the concentration in different units. [Ans. 116 g/L, 13.1% ]
Answer
- Concentration (g/L) = Mass\ of\ solute\ (g) \over Volume\ of\ solution\ (L)
- Percent concentration (%) = Mass\ of\ solute\ (g) \over Mass\ of\ solution\ (g) × 100%
Step 1: Given the information
- Mass of solute = 29 g
- Volume of solution = 250 mL = 0.25 L
Step 2: Calculation of mass of solvent
Mass of solution = 250 g
Mass of solvent = 250 g – 29 g = 221 g
Step 3: Calculation of concentration
Concentration (g/L) = 29 g \over 0.25 L = 116 g/L
Therefore, the concentration in g/L is 116 g/L.
Step 4: Calculation of Percent concentration (%)
Percent concentration (%) = 29\over 221 ×100%
= 13.1 %
