Answer:
T° Freezing solution = - 2.91°C
Explanation:
To solve this, we apply this formula:
ΔT = Kf . m . i
Our solute is SnI₄
ΔT = Freezing T° of pure solvent - Freezing T° of solution
m is molality
i, numbers of ions dissolved.
SnI₄ → Sn⁴⁺ + 4I⁻
5 moles of ions have been formed, 1 mol of Sn⁴⁺ and 4 moles of iodide.
Let's determine molality. Firstly we need the moles of salt.
235 g . 1mol / 626.3 g = 0.375 moles
molality = mol /kg of solvent → 0.375 mol /1.20kg = 0.313 m
Kf reffers to Cryoscopic constant, for water is 1.86°C/m. We replace data at formula → 0°C - T°F solution = 0.313 m . 1.86°C/m . 5
T°F solution = - 2.91°C
