When a monobasic carboxylic acid 14.8 g interacted with an excess of sodium bicarbonate, 4.48 liters

When a monobasic carboxylic acid 14.8 g interacted with an excess of sodium bicarbonate, 4.48 liters of gas were evolved. Determine the formula of the carboxylic acid.

Let’s compose the equation of the reaction of interaction of carboxylic acid with sodium bicarbonate.

R –COOH + NaHCO3 → R –COO – Na + CO2 ↑ + H2O.

Let’s find the amount of acid substance.

n = m: M.

М (R –COOH) = х + 45 g / mol.

n = 14.8 g: (x + 45) g / mol = 4 mol.

Let’s find the quantitative ratios of substances.

Acid and carbon dioxide are in quantitative ratios of 1: 1.

Therefore, their amount of substance will be equal.

Find the amount of carbon monoxide substance.

V = Vn n, where Vn is the molar volume of gas, equal to 22.4 l / mol, and n is the amount of substance.

n = V: Vn,

n = 4.48 mol: 22.4 L / mol = 0.2 mol.

Let’s make a proportion.

14.8: (x + 45) = 0.2.

X + 45 = 14.8: 0.2,

X + 45 = 74,

X = 74 – 45,

X = 29.

Find the molecular weight of the acid.

29 + 45 = 74

45g / mol – carbonyl group – COOH.

The rest is made up of carbon and hydrogen atoms.

Н3С –СН2 –СООН – acetic acid.

Answer: acetic acid.