Question

A chemical reaction, $A \rightleftharpoons B$, is said to be in equilibrium when:
A.Rate of forward reaction is equal to rate of backward reaction
B.Conversion of A to B is only 50% complete
C.Complete conversion of A to B has taken place
D.Only 25% conversion of A to B has taken place

Answer 1

Hint: We can say that the equilibrium constant of a chemical reaction deals with the relationship between the products and reactants when a chemical reaction attains equilibrium. The equilibrium constant of chemical reaction is represented by symbol K.

Complete answer:
We have to know that for a chemical reaction, the equilibrium constant could be defined as the ratio between the quantity of reactant and the quantity of product which is used to determine chemical behaviour.
It is mandatory to notice that there are several different types of equilibrium constants that provide relationships between the products and the reactants of equilibrium reactions in terms of several various units.
Rate of the forward reaction is the same as the rate of the backward reaction at equilibrium.
We can list out some of the characteristics of equilibrium constant are,
Equilibrium constant is independent of initial concentrations of the reactants, the direction from reactant or product which equilibrium is reached.
Equilibrium constant provides a relative idea about the extent to which the reaction occurs.
At a given temperature, the equilibrium constant of a particular reaction has fixed value.
If the value of the equilibrium constant is large, then the forward reaction occurs nearing completion whereas backward reaction to a little extent.
If the forward reaction is exothermic, then the value of equilibrium constant decreases.
In a reversible reaction, the value of equilibrium constant of forward reaction is inverse of value of equilibrium constant of backward reaction,
At equilibrium, the value of equilibrium constant is dependent on the stoichiometry of reactants, and products.
At equilibrium, for a chemical reaction $A \rightleftharpoons B$ the rate of forward reaction is the same as the rate of backward reaction.
Therefore, the option (A) is correct.

Note:
We must remember that at the constant pressure and temperature, for a chemical reaction the value of equilibrium constant is the same. But if there is change in temperature and pressure, there would be change in the equilibrium constant as well. The catalyst has no effect in the equilibrium constant but the rate of reaction is affected.