This question is about carboxylic acids.
Carboxylic acids belong to a homologous series.
Table 1 shows information about three carboxylic acids in this homologous series.
| Name | Formula | pH of a 0.01 mol/dm30.01\text{ mol/dm}^30.01 mol/dm3 solution |
|---|---|---|
| Methanoic acid | (i) | 2.91 |
| Ethanoic acid | CH3COOH\text{CH}_3\text{COOH}CH3COOH | 3.39 |
| (ii) | CH3CH2COOH\text{CH}_3\text{CH}_2\text{COOH}CH3CH2COOH | 3.44 |
Complete Table 1 by giving the chemical formula representing (i) and the name representing (ii).
Methanoic acid ionises in water.
The equation for the reaction is:
HCOOH(aq)⇌HCOO−(aq)+H+(aq)\text{HCOOH(aq)} \rightleftharpoons \text{HCOO}^-\text{(aq)} + \text{H}^+\text{(aq)}HCOOH(aq)⇌HCOO−(aq)+H+(aq)
Explain how the equation shows that methanoic acid is a weak acid.
A technician reacts a solution of methanoic acid with calcium carbonate in an open beaker placed on an electronic balance.
Explain what happens to the reading on the balance during the reaction.
The technician compares the rate of reaction of calcium carbonate with:
The rate of the reaction with methanoic acid is greater than the rate of the reaction with ethanoic acid.
Explain why.
You should refer to ions in your answer and use information from Table 1.