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Solutions — Chemistry STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceChemistrySolutions5 Marks
Question
  1. Define the following terms:
  1. Ideal solution.
  2. Azeotrope.
  3. Osmotic pressure.
  1. A solution of glucose $(C_6H_{12}O_6)$ in water is labelled as $10\%$ by weight. What would be the molality of solution?
(Molar mass of glucose = $180 g mol^{-1}$).
✓

Answer

  1.  
  1. Ideal Solution: Those solutions which follows Raoult’s law under all conditions of temperature and pressure.
  2. Azeotrope: A liquid mixture which distills at constant temperature without under going any change in composition is called Azeotrope.
  3. Osmotic Pressure: The minimum excess pressure that has to be applied on the solution side to prevent the entry of the solvent in to the solution through the semi - permeable membrane is called osmotic pressure.
  1. Given Molecular mass of Glucose = 180, % by wt = 10
$\text{M}=\frac{\text{1000}\times\text{wt%}}{\text{(100-wt%)}\times\text{mol. wt. of solute}}$ OR $\text{M}=\frac{\text{w}\times\text{1000}}{\text{M}\times\text{W}}$
$\text{M}=\frac{\text{1000}\times\text{10}}{\text{(100-10)}\times\text{180}}$
$\text{M}=\frac{\text{10000}}{\text{90}\times\text{180}}$
m = 0∙617m.

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