1. Tardigrade
  2. Question
  3. Chemistry
  4. The molar mass of the solute sodium hydroxide obtained from the measurement of the osmotic pressure of its aqueous solution at 27° C is 25 g mol -1. Therefore, its ionization percentage in this solution is

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Q. The molar mass of the solute sodium hydroxide obtained from the measurement of the osmotic pressure of its aqueous solution at $27^{\circ} C$ is $25 \,g \,mol ^{-1}$. Therefore, its ionization percentage in this solution is

J & K CETJ & K CET 2009Solutions

Solution:

van't Hoff factor,
$i=\frac{\text { observed molar mass }}{\text { calculated molar mass }}$
$=\frac{40}{25}=1.6$
Since, sodium hydroxide is binary electrolyte,
$i=[1+(2-1) \alpha](\alpha=$ degree of ionisation)
$1.6=(1+\alpha) \alpha$
$=1.6-1=0.6=60$