Mol.wt. =ΔTf×Wkf×w×1000=0.23×1251.86×0.85×1000≈55gm Where w=0.85 gW=125 gΔTf=0∘C−(−23∘C)=23∘C Now, i=Mobserved Mnormal =55136.3=2.47 1−αZnCl2⇋αZn+++2α2Cl−Van’t Hoff factor ( i ) =11−α+α+2α=2.47∴α=0.735=73.5%
A solution containing 0.85 ~g of ZnCl_2 in 125.0 ~g of water freezes at -0.23° C. The apparent degree of dissociation of the salt is (K_f . for water…
JEE Main 2012 — Chemistry Physical Chemistry
A solution containing 0.85 g of ZnCl2 in 125.0 g of water freezes at −0.23∘C. The apparent degree of dissociation of the salt is (Kf for water =1.86 K kg mol−1, atomic mass: Zn=65.3 and Cl=35.5)
Held on 12 May 2012 · Verified 6 Jul 2026.
Options
- A
1.36%
- B
73.5%
- C
7.35%
- D
2.47%
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