Answer
$C_{10}H_{12}O_2$
Work Step by Step
B.p. elevation: $61.82-61.70=0.12^{\circ}C$
Molality: $\Delta T_b=K_b,m\rightarrow m=0.12^{\circ}C\div3.63^{\circ}C/m=0.033\ mol/kg$
Number of mols: $0.033\ mol/kg\times(25/1000)kg=8.26\times10^{-4}\ mol$
Molar mass: $0.135\ g\div 8.26\times10^{-4}\ mol=163.35\ g/mol$
Molar mass of empirical formula: $82.10\ g/mol$
Ratio of the molar masses: $163.35\div 82.10=1.99\approx 2$
Molecular formula: $C_{10}H_{12}O_2$
