Introduction:
In this experiment, a mixture of methane and ethane gas is reacted with oxygen in the presence of an electric spark. The resulting gases are then passed through a KOH solution to observe any further contraction in volume.

Step 1: Combustion Reaction:
The combustion reaction of methane (CH4) and ethane (C2H6) with oxygen (O2) can be represented as follows:

CH4 + 2O2 → CO2 + 2H2O
C2H6 + 7/2O2 → 2CO2 + 3H2O

This reaction shows that one molecule of methane reacts with two molecules of oxygen to produce one molecule of carbon dioxide and two molecules of water. Similarly, one molecule of ethane reacts with seven half-molecules of oxygen to produce two molecules of carbon dioxide and three molecules of water.

Step 2: Initial Volume Contraction:
The initial volume of the mixture of methane and ethane, along with the required volume of oxygen, is 100 ml. When the electric spark is applied, the gases undergo combustion and the resulting gases occupy a smaller volume of 212 ml. This contraction in volume is due to the formation of carbon dioxide and water, which have a lower volume compared to the initial reactants.

Step 3: Passing Gases through KOH solution:
The resulting gases, which mainly consist of carbon dioxide and water vapor, are passed through a KOH (potassium hydroxide) solution. KOH is a strong alkali and it reacts with carbon dioxide to form potassium carbonate (K2CO3) and water.

CO2 + 2KOH → K2CO3 + H2O

Step 4: Further Volume Contraction:
When the gases pass through the KOH solution, the carbon dioxide reacts with KOH to form potassium carbonate and water. This reaction leads to a further contraction in volume, as the carbon dioxide is consumed in the reaction.

The exact amount of further volume contraction cannot be determined without additional information about the amount of KOH solution used and the concentration of KOH. However, it can be concluded that there will be a decrease in volume due to the reaction between carbon dioxide and KOH.

Conclusion:
The initial volume contraction observed after the combustion of methane and ethane with oxygen is due to the formation of carbon dioxide and water. When the resulting gases are passed through a KOH solution, a further contraction in volume is expected due to the reaction between carbon dioxide and KOH. The exact amount of further volume contraction depends on the amount and concentration of KOH used.

Nyc darshit