1. Tardigrade
  2. Question
  3. Chemistry
  4. The freezing point of a solution containing 36 g of a compound (empirical formula: CH 2 O ) in 1.20 kg of water is found to be 0.93° C. The molecular formula of the solute is (Kf. of water is .1.86 K Kgmol -1)

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Q. The freezing point of a solution containing 36g of a compound (empirical formula: CH _{2} O ) in 1.20 \,kg of water is found to be 0.93^{\circ} C. The molecular formula of the solute is \left(K_{f}\right. of water is \left.1.86 \,K Kgmol ^{-1}\right)

Solution:

\Delta f=K_{f} \times m
0.93\, K=1.86 \times \frac{36 / M}{1.20}
M=\frac{1.86 \times 36}{0.93 \times 1.2}=60\, g\,mol ^{-1}
n=\frac{\text { Molar mass }}{\text { Empirical formula mass }}
n=\frac{60}{30}=2
Hence molecular formula =\left( CH _{2} O \right) \times 2= C _{2} H _{4} O _{2}