Question

Write the answers to the questions by observing the following figure.

1. Write the chemical reaction shown in the figure above in the form of a balanced equation.
2. Write the name of the gas coming out of the large test tube in the above chemical reaction.
3. Why do small bubbles of lime appear in the small test tube?
4. What is the change in colour of lime net?

Answer 1

1. Balanced equation of the reaction between acetic acid and sodium carbonate is as follows:
   \[\ce{\underset{\text{Acetic acid}}{2CH3COOH_{(aq)}} + \underset{\text{carbonate}}{\underset{\text{Sodium}}{Na2CO_{3(s)}}} -> \underset{\text{ethanoate}}{\underset{\text{Sodium}}{2CH3COONa_{(aq)}}} + \underset{\text{Water}}{H2O_{(l)}} + \underset{\text{Carbon dioxide}}{CO2\uparrow}}\]
2. The gas formed in the large test tube is carbon dioxide (CO₂) gas.
3. The bubbles appear because the carbon dioxide gas generated by the reaction in the large test tube travels through the gas delivery tube and is released into the lime water.
4. The freshly prepared lime water turns milky (or cloudy white). This colour change happens because the carbon dioxide gas reacts with the lime water (calcium hydroxide) to form an insoluble white precipitate of calcium carbonate \[\ce{CaCO3}\]