The unknown alcohol = 2-propanol
Further explanation
Given
volume = 50 ml
mass = 39.4 g
Required
The unknown alcohol
Solution
Density of sample :
= mass : volume
= 39.4 g : 50 ml
= 0.788 g/ml
The unknown alcohol at room temperature = liquid, so the unknown alcohol is 2-propanol because it has temperature range between -90 to 82 for liquid and the density = 0.788 g/ml