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 |
|---|---|---|
| (i) | HCOOH\text{HCOOH}HCOOH | 2.91 |
| Ethanoic acid | CH3COOH\text{CH}_3\text{COOH}CH3COOH | 3.39 |
| Propanoic acid | (ii) | 3.44 |
Complete Table 1 by giving the name representing (i) and the chemical formula 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 student adds a solution of methanoic acid to excess calcium carbonate in an open beaker on a digital balance.
Explain what happens to the mass of the beaker and its contents during the reaction.
The student compares the rates 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.