Question

To make a saturated solution, 36 gm of sodium chloride is dissolved in 100 gm of water at 293 K. Find its concentration at this temperature.

Answer 1

Mass percent-

• Mass percent is a way of expressing a concentration or describing part of particular mixture.
• The composition of the solution can be expressed by mass percentage indicating the amount of solute present in the given mass of solution.
• The solute value is expressed in mass or in moles.
• For a solution, mass per cent is defined as solute grams per gram of solution, multiplied by $100$ to obtain a percentage.

Effect of temperature-

• When temperature increases, solubility starts increasing.
• When temperature decreases, solubility starts decreasing.

Step I: Find total mass of solution

• Mass of sodium chloride ($\mathrm{NaCl}$ as solute)= $36gm$
• Mass of water (${\mathrm{H}}_2\mathrm{O}$ as solvent)= $100gm$
• Mass of solution $$\begin{gathered} =36+100 \\ =136gm \end{gathered}$$

Step II: Find concentration

• $\mathrm{Concentration}=\left(\frac{\mathrm{Mass}\mathrm{of}\mathrm{solute}}{\mathrm{Mass}\mathrm{of}\mathrm{solution}}\right)*100$
• $\mathrm{Concentration}=\frac{36}{136}*100$
• $\mathrm{Concentration}=26.47\%$

Hence, concentration of given solution came out to be $26.47\%$.