Question

If the reaction equation is $nA + mB\underset {} \longleftrightarrow xC + yD$. What is the equilibrium equation?
A-$K = {\left[ C \right]^x}{\left[ D \right]^y}/{\left[ A \right]^n}{\left[ B \right]^m}$
B-$K = {\left[ A \right]^n}{\left[ B \right]^m}/{\left[ C \right]^x}{\left[ D \right]^y}$
C-$K = {\left[ A \right]^n}{\left[ B \right]^m}/{\left[ A \right]^n}{\left[ B \right]^m}$
D-$K = {\left[ C \right]^x}{\left[ A \right]^y}/{\left[ A \right]^n}{\left[ D \right]^m}$
E-$K = \left[ C \right]\left[ D \right]/\left[ A \right]\left[ B \right]$

Answer 1

Hint: We know that, the equilibrium constant relates the amount of reactant and products of the equilibrium reaction. It is a numerical value of the given reaction at a given temperature.

Complete step by step answer:
In a balanced chemical equation, the number of atoms of the reactants is equal to the number of atoms of the products. The coefficients of the balanced equation are stoichiometric coefficients and these coefficients are important to relate the amount of reactants and products in the equilibrium constant. In equilibrium expression, the concentration of reactant and product at equilibrium is related. The numerator of the expression has the concentrations of the product and the denominator of the expression has the concentration of the product.
Now, we consider the reaction.
$nA + mB\underset {} \longleftrightarrow xC + yD$
The equilibrium equation is written as,
$K = \dfrac{{{{\left[ C \right]}^x}{{\left[ D \right]}^y}}}{{{{\left[ A \right]}^n}{{\left[ B \right]}^m}}}$
Where, $\left[ A \right],\left[ B \right],\left[ C \right],\left[ D \right]$ are the concentration of the species at equilibrium and the coefficients in the reactions are raised to the power in the expression for equilibrium constant.

$\therefore $The correct answer is an option A..

Note: For non-equilibrium reactions we can write the same expression called the reaction Quotient Q which is equal to the K.
Q and K is used to calculate the concentration of the substances and also used to determine whether the reaction favors product or reactants at equilibrium.
The difference between the Q and K is that the value of Q changes if the reaction approaches equilibrium whereas K is based on the concentration of the reaction.