a.Calculate the depression in freezing point (Delta T_(f)) of 0.1 m solution of ROH in cold conc. H_(2)SO_(4) . K_(f) = x K kg mol^(-1) b.Calculate the Delta T_(1) of 0.2 m solution of Ph_(3) C--OH in cold conc.H_(2)SO_(4) . K_(f) = x K kg mol^(-1) .

a.Calculate the depression in freezing point (Delta T_(f)) of 0.1 m so

1.	a.Calculate the depression in freezing point (Delta T_(f)) of 0.1 m solution of ROH in cold conc. H_(2)SO_(4) . K_(f) = x K kg mol^(-1) b.Calculate the Delta T_(1) of 0.2 m solution of Ph_(3) C--OH in cold conc.H_(2)SO_(4) . K_(f) = x K kg mol^(-1) .
Answer» Solution :a.ROH reacts with cold cons. `H_(2)SO_(4)` as follows: 1.`ROH + H_(2)SO_(4) rarr RO^(o+)H_(2) + HSO_(4)^(-) rarr ROSO_(2)OH` + `cancel (H_(2)O)` 2.`{:(H_(2)SO_(4)+cancel(H_(2)O)toH_(3)O^(o+)+HSO_(4)^(-)),(ulbar(ROH+2H+2H_(2)SO_(4)toROSO_(2)OH+H_(3)O^(o+)+HSO_(4)^(-))):} Number of moles of particles formed per mole of solute (i) (van't Hoff factor) = 3 (The reaction does not produce `R^(o+)`, because `R^(o+)` ion or even `R_(3)C^(o+)` ion is not stable enogh to PERSIST. `:. Delta T_(f) = i K_(f)xxM` `= 3x xx 0.1 = 0.3x K` b.`Ph_(3)C---OH` reacts with cold conc.`H_(2)SO_(4)` as follows: 1.`Ph_(3)COH + H_(2)SO_(4) rarr Ph_(3)C^(o+)` + `cancel (H_(2)O)` + `HSO_(4)^(-)` 2.`{:(H_(2)SO_(4)+cancel(H_(2)O)toH_(3)O^(o+)+HSO_(4)^(-)),(ulbar(Ph_(3)COH+2H+2H_(2)SO_(4)toPh_(3)C^(o+)+H_(3)O^(o+)+2HSO_(4)^(-))):} Number of moles of particles formed per mole of solute (i) (Van't Hoff factor) = 4 (The reaction PRODUCES stable `Ph_(3)C^(o+)` ion due to resonance stabilisation, and `Ph_(3)C^(o+)` PERSISTS in the solution.) `:. Delta T_(f) = i K_(f)xxM` `= 4x xx 0.2 = 0.8x K`.