Chemistry: Tert-butyl alcohol is a solvent with a kf of 9.10 ∘c/m and a freezing point of 25.5 ∘c. when 0.807 g of an unknown colorless liquid was dissolved in 11.6 g of tert-butyl alcohol, the solution froze at 15.3 ∘c.which of the following is most likely the identity of this unknown liquid? tert-butyl alcohol is a solvent with a of 9.10 and a freezing point of 25.5 . when 0.807 of an unknown colorless liquid was dissolved in 11.6 of tert-butyl alcohol, the solution froze at 15.3 .which of the following

I believe it s a checmical change. Explanation:...

Tert-butyl alcohol is a solvent with a kf of 9.10

cadeduncan71

18.01.2022

ethylene glycol (molar mass = 62.07 g/mol)

Explanation:

Depression in freezing point :

Formula used for lowering in freezing point is,

$\Delta T_f=k_f\times m$

or,

$\Delta T_f=k_f\times \frac{\text{mass of solute}}{\text{molar mass of solute}\times \text{weight of solvent in kg}}$

where,

T_f = change in freezing point

k_f = freezing point constant= 9.10^0C/m

m = molality

Given mass of solute = 0.807 g

Molar mass of solute=? g/mol

weight of solvent in kg= 11.6 g=0.0116 kg

$\Delta T_f=T^{o}_f-T_f=25.5^0C-15.3^0C)=10.2^0C$

$10.2=9.10\times \frac{0.807}{\text{molar mass of solute}\times 0.0116kg}$

${\text{molar mass of solute}}=62.07 g/mol$

Thus the solute is ethylene glycol which has same molecular mass as calculated, i.e 62.07 g/mol.

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