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Given below are two statements :
Given : Molar mass of C, H, O, Cl are 12, 1, 16 and 35.5 g mol$$^{-1}$$, respectively
Statement I : In 30% (w/w) solution of methanol in CCl$$_4$$(at T K), the mole fraction of CCl$$_4$$ is equal to 0.33.
Statement II : Mixture of methanol and CCl$$_4$$ shows positive deviation from Raoult's law.
In the light of the above statements, choose the correct answer from the options given below :
Statement I : In 30% (w/w) solution of methanol in CCl$$_4$$(at T K), the mole fraction of CCl$$_4$$ is equal to 0.33.
30% (w/w) methanol in $$\mathrm{CCl_4}$$ means:
No. of Moles :
For Methanol: $$M=12+4\left(1\right)+16=32$$
$$n_{CH_3OH}=\frac{30}{32}=0.9375$$
For $$CCl_4$$: $$M=12+4(35.5)=154$$
$$n_{CCl_4}=\frac{70}{154}=0.4545$$
Mole Fraction of $$CCl_4$$:
$$X_{CCl_4}=\ \frac{0.4545}{0.4545+0.9375}=\frac{0.4545}{1.392}\approx\ 0.326\approx\ 0.33$$
So Statement I is correct.
Statement II : Mixture of methanol and CCl$$_4$$ shows positive deviation from Raoult's law.
Methanol has strong hydrogen bonding, while $$\mathrm{CCl_4}$$ is non-polar.
When mixed:
Therefore vapour pressure becomes higher than expected.
Hence the mixture shows:
Positive Deviation from Raoult's Law
Statement II is Correct,
Hence, Option A is correct.
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