Question

One litre $C{O_2}$ is passed through red hot coke. The volume becomes $1.4\,L$ at the same time temperature and pressure. Write the composition of the product.

Answer 1

Hint : In a balanced chemical reaction the no of moles or the volume concentration remains constant in the ratio of their stoichiometric coefficient. The temperature and the pressure remain the same throughout the reaction.

Complete Step By Step Answer:
First let’s write the equation for the above-mentioned reaction
$C{O_2} + \,C\, \to \,2CO$
The above-mentioned reaction is as follows in which if let’s say $x\,L$ of carbon dioxide reacts with coke then $2x\,L$ of carbon monoxide will be formed as the reaction is already balances, 2 units carbon forming on both sides and 2 units of oxygen forming on both sides.
Initially just one litre of carbon dioxide is taken and reacted with coke and in the end solution is $1.4\,L$ .
Now if $x\,L$ carbon dioxide reacts with $x\,L$ of coke to form $2x\,L$ of carbon monoxide.
Remaining amount of carbon monoxide if it was one litre initially is $1 - x$
And the final solution quantity is $1.4\,L$
Therefore, we can say that the remaining carbon dioxide and the forming carbon monoxide forms the final solution, therefore,
It can be written as $(1 - x) + 2x = 1.4$
Solving the above equation
$(1 - x) + 2x = 1.4 \\\ \Rightarrow 1 + x = 1.4 \\\ \Rightarrow x = 0.4\,L \\\$
If $x = 0.4\,L$ then,
Concentration of carbon dioxide left is equal to $1 - x$ , solving for x we get $= 1 - 0.4 = 0.6\,L$
And the concentration of carbon monoxide is $2x\,L$ , solving we get $2 \times 0.4 = 0.8\,L$
On reaction the final products come out to be the leftover carbon dioxide and the newly formed carbon monoxide.
The final composition product is 0.6L\,C{O_{2\,}}\ & \,0.8L\,CO , respectively being carbon dioxide and carbon monoxide.

Note :
In the non-ideal situation when the pressure and temperature also change you have to first find the moles using the real gas equation and then use the stoichiometric equation.