Question

If an equal number of moles of reactants are used, do the following equilibrium mixtures contain primarily reactants or products? Please note this question has 1 submission for each part. (a) HCN(aq) + H2O(l) equilibrium reaction arrow CN −(aq) + H3O+(aq) K = 6.2 10-10 products reactants (b) H2(g) + Cl2(g) equilibrium reaction arrow 2 HCl(g) K = 2.51 104 reactants products

Answer 1

Answer:

For a: The equilibrium mixture contains primarily reactants.

For b: The equilibrium mixture contains primarily products.

Explanation:

There are 3 conditions:

• When $K_{eq}>1$; the reaction is product favored.
• When $K_{eq}$; the reaction is reactant favored.
• When $K_{e}=1$; the reaction is in equilibrium.

For the given chemical reactions:

• For a:

The chemical equation follows:

$HCN(aq.)+H_2O(l)\rightleftharpoons CN^-(aq.)+H_3O^+(aq.);K_{eq}=6.2\times 10^{-10}$

The expression of $K_{eq}$ for above reaction follows:

$K_{eq}=\frac{[CN^-][H_3O^+]}{[HCN][H_2O]}=6.2\times 10^{-10}$

As, $K_{eq}$, the reaction will be favored on the reactant side.

Hence, the equilibrium mixture contains primarily reactants.

• For b:

The chemical equation follows:

$H_2(g)+Cl_2(g)\rightleftharpoons 2HCl(g);K_{eq}=2.51\times 10^{4}$

The expression of $K_{eq}$ for above reaction follows:

$K_{eq}=\frac{[HCl]^2}{[H_2][Cl_2]}=2.51\times 10^{4}$

As, $K_{eq}>1$, the reaction will be favored on the product side.

Hence, the equilibrium mixture contains primarily products.