JEE Mains · Chemistry · STD 12 -1. Solution and colligative properties
\(20 \%\) of acetic acid is dissociated when its \(5\,g\) is added to \(500\,mL\) of water. The depression in freezing point of such water is \(.....\times 10^{-3} \;{ }^{\circ} C\). Atomic mass of \(C , H\) and \(O\) are \(12,1\) and \(16\,a.m.u.\) respectively. [Given : Molal depression constant and density of water are \(1.86\, K\, kg\, mol^{-1}\) and \(1\, g\, cm^{-3}\) respectively.]
- A \(371\)
- B \(372\)
- C \(373\)
- D \(375\)
Answer & Solution
Correct Answer
(B) \(372\)
Step-by-step Solution
Detailed explanation
\(i =1+( n -1) \alpha\) \( i =1+0.2(2-1)=1.2\) \(\Delta T _{ f }= i K _{ f } m\) \(\Delta T _{ f }=1.2 \times 1.86 \times \frac{5 \times 1000}{60 \times 500}\) \(\Delta t _{ f }=3.72\) \(\Delta T _{ f }=372 \times 10^{-2}\)
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