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QJEEM23Chd0c9: JEE Main 2023 Chemistry - Class 12 JEEM23Chd0c9 Solution: of acetic acid is dissociated when its is added to of water.…

20%20 \% of acetic acid is dissociated when its 5 g5 \mathrm{~g} is added to 500 mL500 \mathrm{~mL} of water. The depression in freezing point of such water is _________ ×10−3∘C\times 10^{-3}{ }^{\circ} \mathrm{C} .

Atomic mass of C,H\mathrm{C}, \mathrm{H} and O\mathrm{O} are 12,1 and 16 a.m.u. respectively.

[Given : Molal depression constant and density of water are 1.86 K kg mol−11.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1} and 1 g cm−31 \mathrm{~g} \mathrm{~cm}^{-3} respectively.]

Step-by-Step Verified Solution

amp;i=1+(n−1)αamp;⇒i=1+0.2(2−1)=1.2amp;ΔTf=iKKfmamp;ΔTf=1.2×1.86×5×100060×500amp;Δtf=0.372amp;ΔTf=372×10−3\begin{aligned} & \mathrm{i}=1+(\mathrm{n}-1) \alpha \\\\ & \Rightarrow \mathrm{i}=1+0.2(2-1)=1.2 \\\\ & \Delta \mathrm{T}_{\mathrm{f}}=\mathrm{i} \mathrm{K} \mathrm{K}_{\mathrm{f}} \mathrm{m} \\\\ & \Delta \mathrm{T}_{\mathrm{f}}=1.2 \times 1.86 \times \frac{5 \times 1000}{60 \times 500} \\\\ & \Delta \mathrm{t}_{\mathrm{f}}=0.372 \\\\ & \Delta \mathrm{T}_{\mathrm{f}}=372 \times 10^{-3}\end{aligned}

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