Aforensic chemist is given a white powder for analysis. she dissolves 0.50 g of the substance in 8.0 g of benzene. the solution freezes at 3.9°c. can the chemist conclude that the compound is cocaine (c17h21n04)? what assumptions are made in the analysis? the freezing point of benzene is 5.5°c.

The given compound cannot be cocaine.

Explanation:

The chemist can comment on the nature of compound being cocaine or not from the depression in freezing point.

Depression in freezing point of is related to molality as:

Depression in freezing point = Kf X molality

Where

Kf = cryoscopic constant = 4.90°C/m

depression in freezing point = normal freezing point - freezing point of solution

depression in freezing point = 5.5-3.9 = 1.6°C

1.6°C = 4.90 X molality

we know that:

therefore

moles = 0.327X0.008 = 0.00261 mol

The molar mass of cocaine is 303.353

So the given compound cannot be cocaine.