What will be the freezing point of a solution made by dissolving 5.25 g of naphthalene (C10H8) in 100.0 g benzene (C6H6?). The normal freezing point of benzene is 5.5°C and K f (benzene) is 5.12°C / m.

Answer 1

mols naphthalene = grams/molar mass = ?
molality = m = mols naphthalene/kg solvent
Then delta T = Kf*m and solve for delta T. Subtract from the normal freezing point to arrive at the new freezing point.

Answer 2

3.4