At what temperature will water freeze if 100g NaCl are dissolved in 500g H2O?

water's Kf = 1.86 °C/m

Answer : The temperature at which water freeze will be,

Explanation :  Given,

Molal-freezing-point-depression constant for water =

Mass of NaCl (solute) = 100 g

Mass of water (solvent) = 500 g  = 0.500 kg

Molar mass of NaCl = 58.5 g/mole

Formula used :  

where,

= change in freezing point

= freezing point of solution = ?

= freezing point of water =

i = Van't Hoff factor = 2  (for NaCl electrolyte)

= freezing point constant for water =

m = molality

Now put all the given values in this formula, we get

Therefore, the temperature at which water freeze will be,

10 years is the answer