LAQ : 250 mL of a NaCl solution contains 29 g of NaCl dissolved in water. Express the concentration in different units.

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 %