Question

Ethylene glycol is used as an antifreeze in a cold climate. Mass of ethylene glycol which should be added to 4 kg of water to prevent it from freezing at $-6^{o}C$ will be $(K_f$ for water $=1.86Kkg$ $mo{l}^{-1}$, and molar mass of ethylene glycol $=62gmo{l}^{-1}$)

• A. $804.32$ gm
• B. $204.30$ gm
• C. $400.00$ gm
• D. $304.60$ gm

Answer 1

The correct option is A $804.32$ gm

$\Delta T_f=k_f.m=0-(-6)=1.86m$
$m=\frac{6}{1.86}$ i.e., $=\frac{6}{1.86}$ mole in 1 kg.
$\therefore \frac{6}{1.86}\times 4$ mole in 4 kg.
Wt $=\frac{6}{1.86}\times 4\times 62=804.32$ gram

Hence, the correct option is $A$