Agar titik beku turun menjadi -6C (Kf air=1,86) maka ke dalam 10 liter air dilarutkan etilen glikol (Mr=62) sebanyak a. 5 kg b.4 kg c.3 kg d.2 kg e.1 kg

6 = x / 62 . 1000 / 10 . 1.86 . 1
x = 2 kg (D) -> Jawab

Kf air= 1,86 °C / m
Tf' = - 6°C
V air = 10 L
m air = 10 kg
Mr = 62
Tf = 0°C

∆Tf = Tf - Tf'
∆Tf = 0°C - ( - 6) °C
∆Tf = 6 °C

∆Tf = Kf air × molalitas
molalitas = ∆Tf / Kf
molalitas = 6°C / 1,86°C/m
molalitas = 3,226 m

molalitas = ( m eg / Mr ) / m air
m eg = molalitas × m air × Mr
m eg = 3,226 m × 10 kg × 62
m eg = 2000 gr = 2 kg

Jawaban : D. 2 kg