Answer:
Formula for the salt: MCl₃
Explanation:
MClₓ → M⁺ + xCl⁻
We apply the colligative property of boiliing point elevation.
We convert the boiling T° to °C
375.93 K - 273K = 102.93°C
ΔT = Kb . m . i
where ΔT means the difference of temperature, Keb, the ebulloscopic constant for water, m the molality of solution (mol of solute/kg of solvent) and i, the Van't Hoff factor (numbers of ions dissolved)
ΔT = 102.93°C - 100°C = 2.93°C
Kb = 0.512 °C/m
We replace data: 2.93°C = 0.512 °C/m . m . i
i = x + 1 (according to the equation)
22.9 g / (56g/m + 35.45x) = moles of salt / 0.1kg = molality
We have calculated the moles of salt in order to determine the molar mass, cause we do not have the data. We replace
2.93°C = 0.512 °C/m . [22.9 g / (56g/m + 35.45x)] / 0.1kg . (x+1)
2.93°C / 0.512 m/°C = [22.9 g / (56g/m + 35.45x)] / 0.1kg . (x+1)
5.72 m = [22.9 g / (56g/m + 35.45x)]/ 0.1 (x+1)
5.72 . 0.1 / [22.9 g / (56g/m + 35.45x)] = x+1
0.572 / (22.9 g / (56g/m + 35.45x) = x+1
0.572 (56 + 35.45x) / 22.9 = x+1
0.572 (56 + 35.45x) = 22.9x + 22.9
32.03 + 20.27x = 22.9x + 22.9
9.13 = 2.62x
x = 3.48 ≅ 3
