Question

From an experiment to study the properties of acetic acid, answer the following questions:
(a) Name the substances which in addition to acetic acid produce Carbon dioxide gas. Give a relevant chemical equation for the above?
(b) How is \[C{O_2}\] gas tested in the laboratory?

Answer 1

Hint: We can understand from the question that we have to produce Carbon dioxide gas. Hence we should think along the lines of using carbonates or bicarbonates of some substance that must be reacted with acetic acid (commonly known as Vinegar).

Complete step by step answer:
1 mole of Sodium bicarbonate (Commonly known as baking soda) reacting with 1mole of acetic acid produces 1 mole Carbon dioxide gas, 1 mole of Sodium acetate and 1 mole of water.
Hence, the substance we need to add to acetic acid is Sodium Bicarbonate.
The chemical reaction is as follows:
\[NaHC{O_3}\,(s) + C{H_3}COOH(l) \to \,C{O_2}(g)\, + {H_2}O(l)\, + C{H_3}COONa\]
The gas produced can be tested in the laboratory by passing it through lime water which is transparent. If we see that the lime water turns milky due to formation of Calcium carbonate we can conclude that the gas evolved in the experiment was Carbon dioxide. The gas produced must also be passed through acidified Potassium dichromate solution where it should not produce any observable change.

Additional Information:
We can perform a simple experiment to ascertain if Carbon dioxide is produced. We should take 2 tablespoons of baking soda and add a teaspoon of vinegar to it. We can see that a gas is evolved with effervescence. This gas is Carbon dioxide.

Note: While testing for Carbon dioxide, we must remember to perform the acidified Potassium dichromate test after the lime water test as both Sulphur dioxide and Carbon dioxide turns lime water milky but Sulphur dioxide solution turns acidified potassium chromate solution green whereas carbon dioxide shows no change.