Which of the following pairs of solutions is expected to be isotonic at same temperature?
Which of the following pairs of solutions is expected to be isotonic at same temperature?
\(0.1 \mathrm{M}\) urea and \(0.1 \mathrm{M} \mathrm{NaCl}\)
\(0.1 \mathrm{M}\) glucose and \(0.2 \mathrm{M} \mathrm{NaCl}\)
\(0.1 \mathrm{M} \mathrm{NaCl}\) and \(0.1 \mathrm{M} \mathrm{CH}_3 \mathrm{COOH}\)
\(0.1 \mathrm{M} \mathrm{NaCl}\) and \(0.1 \mathrm{M} \mathrm{KNO}_3\)
Solution
Two solutions of same osmotic pressure \((\pi)\) are isotonic solutions.
\(\begin{aligned}
\pi_1(0.1 \mathrm{M} \mathrm{NaCl}) & =0.1 \times R T \times 2 \\
\pi_2\left(0.1 \mathrm{M} \mathrm{KNO}_3\right) & =0.1 \times R T \times 2
\end{aligned}\)
So, \(\pi,(0.1 \mathrm{M} \mathrm{NaCl})=\pi_2\left(0.1 \mathrm{M} \mathrm{KNO}_3\right)\) at same temperature.