Question #47dc1
1 Answer
Explanation:
Start by writing the balanced chemical equation that describes this equilibrium reaction
#"H"_ (2(g)) + "Cl"_ (2(g)) rightleftharpoons color(red)(2)"HCl"_((g))#
Here hydrogen gas,
Notice that the reaction produces
Now, the equilibrium constant for this reaction,
#K_c = (["HCl"]^color(red)(2))/(["H"_2] * ["Cl"_2])#
In your case, the equilibrium constant at the temperature at which the reaction takes place is equal to
Right from the start, the magnitude of the equilibrium constant tells you that the equilibrium will lie almost entirely to the right, i.e. the reaction will almost go to completion.
The forward reaction, i.e. the reaction that produces hydrogen chloride, will be favored. This means that at equilibrium, you can expect the concentration of hydrogen chloride to be significantly higher than the concentrations of the two reactants.
Rearrange the expression of
#["HCl"]^color(red)(2) = K_c * ["H"_2] * ["Cl"_2]#
This will give you
#["HCl"] = color(red)(sqrt(color(black)(K_c * ["H"_2] * ["Cl"_2]))#
Plug in your values to get
#["HCl"] = sqrt(2.5 * 10^(34) * 3.8 * 10^(-5) * 4.6 * 10^(-6))#
#["HCl"] = color(green)(|bar(ul(color(white)(a/a)2.1 * 10^(12)"M"color(white)(a/a)|)))#
The answer is rounded to two sig figs.
As predicted, the equilibrium concentration of hydrogen chloride is indeed significantly higher than the equilibrium concentrations of the two reactants.