Question

The equilibrium constant for the reaction NO2(g)+NO3(g)→N2O5(g) is 2.1x10-20 , therefore: a. At equilibrium, the concentration of products and reactants is about the same. b. At equilibrium, the concentration of products is greater than the reactants. c. At equilibrium, the concentration of reactants is greater than the products

Answer 1

Answer: c. At equilibrium, the concentration of reactants is greater than the products

Explanation:

Equilibrium constant for a reaction is the ratio of concentration of products to the concentration of reactants each raised to the power its stoichiometric coefficients.

For the reaction:

$NO_2(g)+NO_3(g)\rightleftharpoons N_2O_5(g)$

Equilibrium constant is given as:

$K_{eq}=\frac{[N_2O_5]}{[NO_2]\times [NO_3]}$

$2.1\times 10^{-20}=\frac{[N_2O_5]}{[NO_2]\times [NO_3]}$

When

a) K > 1, the concentration of products is greater than the concentration of reactants

b) K < 1, the concentration of reactants is greater than the concentration of products

c) K= 1, the reaction is at equilibrium, the concentration of reactants is equal to the concentration of products

Thus as $K_{eq}$ is $2.1\times 10^{-20}$ which is less than 1,

the concentration of reactants is greater than the concentration of products