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:
A. Both Statement I and Statement II are true
Statement I: 30\% (w/w) solution of methanol in CCl_4 means 30 g of methanol is present in 70 g of CCl_4. Molar mass of methanol (CH_3OH) = 12 + 4 1 + 16 = 32 g mol^ -1 Molar mass of CCl_4 = 12 + 4 35.5 = 154 g mol^ -1 Moles of methanol = 30 32 = 0.9375 mol Moles of CCl_4 = 70 154 = 0.4545 mol Mole fraction of CCl_4 = 0.4545 0.9375 + 0.4545 = 0.4545 1.392 0.326 0.33 Thus, Statement I is true. Statement II: In pure methanol, molecules are held together by strong intermolecular hydrogen bonding. On adding CCl_4, its molecules come between methanol molecules and break the hydrogen bonds. This decreases the intermolecular attractive forces, leading to an increase in vapour pressure. Hence, the mixture shows a positive deviation from Raoult's law. Thus, Statement II is true. Both Statement I and Statement II are true. Answer: Both Statement I and Statement II are true
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