State Gay-Lussac's law, write an equation for the combustion of ethene, and state the role of aqueous sodium hydroxide in absorbing CO2.

a)

i) State Gay Lussac's law.
Gay Lussac's law states that when gases react, they do so in volumes that bear a simple whole number ratio to one another and to the volumes of the gaseous products, provided that all volumes are measured at the same temperature and pressure.

ii) Write an equation for the reaction that occurred when the mixture of gases was sparked.
The reaction is the complete combustion of ethene (C₂H₄) with oxygen (O₂), producing carbon dioxide (CO₂) and water (H₂O).

$$\text{C}_2\text{H}_4\text{(g)} + 3\text{O}_2\text{(g)} \longrightarrow 2\text{CO}_2\text{(g)} + 2\text{H}_2\text{O(l)}$$

iii) State the role of aqueous sodium hydroxide in the experiment.
Aqueous sodium hydroxide (NaOH) is a strong base that absorbs acidic gases. In this experiment, it absorbs the carbon dioxide ($\text