Answer is: the freezing point of a solution is -1.16°C.
Missing question: Benzene freezes at 5.50°C and its Kf value is 5.12°C/m.
m(C₈H₁₈) = 22.0 g.
n(C₈H₁₈) = m(C₈H₁₈) ÷ M(C₈H₁₈).
n(C₈H₁₈) = 22 g ÷ 114.23 g/mol.
n(C₈H₁₈) = 0.192 mol.
m(C₆H₆ - benzene) = 148.0 g ÷ 1000 g/kg.
m(C₆H₆) = 0.148 kg.
b(solution) = n(C₈H₁₈) ÷ m(C₆H₆).
b(solution) = 0.192 mol ÷ 0.148 kg.
b(solution) = 1.30 mol/kg.
ΔT = Kf(benzene) · b(solution).
ΔT = 5.12°C/m · 1.3 m.
ΔT = 6.66°C.
Tf = 5.50°C - 6.66°C.
Tf = -1.16°C.