Question

Consider this equilibrium4HCl(g) + O2(g) 2H2O(g) + 2Cl2(g)The equilibrium law expression for the balanced chemical equation would be a) 2[H20][Cl2]/ 4[HCI)[02] b) [H20][C|2]/HC1][02]c) [HCl][02] / [H2O][Cl2] d)[HCl]^4[02] / [H20]^2(C12)^2 e) [H20]^2[Cl2]^2/ [HCl]^4[02] [[

Answer 1

Step 1 - Understanding the equilibrium constant

For a chemical reaction:

`aA+bB\rightleftarrows cC+dD`

The equilibrium constant would be:

`K=(\lbrack C\rbrack^c\lbrack D\rbrack^d)/(\lbrack A\rbrack^a\lbrack B\rbrack^b)`

We need to be careful because pure liquids and solids do not enter the equilibrium constant.

Step 2 - Finding the equilibrium constant for the given reaction

For this reaction:

`4\text{HCl}_((g))+O_(2(g))\rightleftarrows2H_2O_((g))+2Cl_(2(g))`

We can see that all substances are in the gaseous state. Therefore, all substances will enter the equilibrium constant. The equilibrium constant in this case will be:

`K=(\lbrack C\rbrack^c\lbrack D\rbrack^d)/(\lbrack A\rbrack^a\lbrack B\rbrack^b)=\frac{\lbrack H_2O\rbrack^2\lbrack Cl_2\rbrack^2}{\lbrack O_2\rbrack^{}\lbrack HCl\rbrack^4}`

The correct answer is thus alternative e).