1) The freezing point (in °C) of solution containing 0.1 g of K3[Fe(CN)6] (molecular weight 329) in 100 g of water (Kf=1.86Kkgmol−1) is A) −2.3×10−2 B) −5.7×10−2 C) −5.7×10−3 D) −1.2×10−2 Answer: Option AExplanation:Vant Hoff's factor (i)=4(3K++[Fe(CN)6]3−) Molality= 0.1329×1000100=1329 ⇒ −△Tf=iKf.m=4×1.86×1329=2.3×10−2⇒Tf=−2.3×10−2oC (As freezing point of water is 00C)