Question

The order of osmotic pressures of equimolar solutions of $ BaCl_{2}, $ $ NaCl $ and glucose will be

• A. $ BaCl_{2} > NaCl > $ glucose
• B. $ NaCl >BaCl_{2} > $ glucose
• C. glucose $ > BaCl_{2} > NaCl $
• D. glucose $ > NaCl > BaCl_{2} $

Answer 1

Answer: (A)

Glucose is an organic compound and this is not ionised while $BaCl _{2}$ and $NaCl$ are inorganic compounds and they are strong electrolytes and are normally $100 \%$ ionised at normal dilution.
$BaCl _{2} \rightleftharpoons Ba ^{2+}+2 Cl ^{-} $
$NaCl \rightleftharpoons Na ^{+}+ Cl ^{-} $
$\because$ Osmotic pressure is a colligative property and hence, depends on the number of ions.
So, decreasing order of osmotic pressure is $BaCl _{2}> NaCl >$ glucose