`K_(f)` for water is `1.86 K kg mol^(-1)`. IF your automobile radiator holds `1.0 kg` of water, how many grams of ethylene glycol `(C_(2)H_(6)O_(2))` must you add to get the freezing point of the solution lowered to `-2.8^(@)C` ?

Options

A. 93 g
B. 39 g
C. 27 g
D. 72 g

Answer

A

Explanation

`Delta T_(f) = 0-(-2.8) = 2.8`
Mass of solvent = 1 kg = 1000g
`Delta T_(f) = (k_(f) xx 1000 xx w_(B))/(w_(A) xx M_(B))`
`2.8 = (1.86 xx 1000 xx w_(B))/(1000 xx 62)`
`w_(B) = (2.8 xx 1000xx 62)/(1.86 xx 1000) = 93.3 g`