Alkanes are non-polar so only have London forces between them. These intermolecular bonds are weak, and easily overcome with little energy. This means that alkanes have a low boiling point hence they are gases at room temperature. Alcohols also have London forces between them, but they also have hydrogen bonds between them due to the highly electronegative oxygen atom attached to a hydrogen atom in the hydroxyl group. This means more energy is required to overcome the intermolecular forces between alcohols, hence they have a higher boiling point than alkanes, and are typically liquids at room temperature.