Solutions Question 365
Question: If sodium sulphate is considered to be completely dissociated into cations and anions in aqueous solution, the change in freezing point of water $ ( \Delta T_{f} ), $ when 0.01 mol of sodium sulphate is dissolved in 1 kg of water, is $ ( K_{f}=1.86Kkgmo{l^{-1}} ) $
Options:
A) 0.372 K
B) 0.0558 K
C) 0.0744 K
D) 0.0186 K
Show Answer
Answer:
Correct Answer: B
Solution:
Sodium sulphate dissociates as $ Na_2SO_4( s )\xrightarrow{{}}2N{a^{+}}+SO_4^{-} $ hence van’t hoff factor i = 3 Now $ \Delta T_{f}=ik_{f}.m $
$ =3\times 1.86\times 0.01=0.0558K $
