Some saturated monohydric alcohol contains 34.8% oxygen by weight. What is this alcohol?

Solution:
1. Let’s write down the general formula of the limiting monohydric alcohol:
СnH2n + 1OH, where W (O) = 34.8%;
From which it follows: W (O) = 16 * M (CnH2n + 1OH);
M (CnH2n + 1OH) = 16 / 0.348;
M (CnH2n + 1OH) = 45.98 = 46 g / mol;
2. Find the number of atoms C (carbon) by the formula: СnH2n + 1OH;
M = 12n + 2n + 1 + 16 + 1;
14n + 18 = 46;
14n = 27.98;
N = 1.99 = 2;
3. Formula of alcohol: C2H5 – OH; M (C2H5OH) = 12 * 2 + 6 + 16 = 46 g / mol.
The name of the limiting monohydric alcohol is ethanol.
Answer: С2Н5ОН – ethyl alcohol.