The mass fraction of oxygen in the saturated monobasic carboxylic acid is 43.24%.

The mass fraction of oxygen in the saturated monobasic carboxylic acid is 43.24%. Establish the molecular formula of the acid.

Let’s write down the data on the condition of the problem:
CxHyOz – saturated monobasic acid

W (O) = 43, 24%

Establish the formula: ShNuO -?

Determine the amount of oxygen:
Y (O) = 43.24 / 12 = 2.7 mol.

Based on the general formula, we calculate the number of carbon atoms:
CnH2n + 1COOH;

Mr (CxHyOz) = 100 w.ch

12n + 2 + 1 + 12 + 32 + 1 = 100;

14n = 100 – 48;

14n = 52;

n = 3, 7 = 4

Let’s establish the formula: С4Н8О2

H3C – CH2 – CH2 – COOH – butanoic acid (butyric acid).

Answer: C3H7 – COOH – butyric acid.