The correct option is B Hydrogen ion concentration will decrease
The equilibrium reaction is CO2+H2O⇌H2CO3⇌H++HCO−3.
When some CO2 escapes from the body, the equilibrium will shift to left so that more CO2 is produced which will nullify the effect of lost CO2. Due to this, the hydrogen ion concentration will decrease.
Theory:
Effect of change in concentration of reactant and/or product :
In an equilibrium, increasing the concentrations of reactants results in shifting the equilibrium in favour of products while increasing the concentration of the product, results in shifting the equilibrium in favour of the reactants.
Case 1: Q becomes less than Keq:
Consider a reaction in equilibrium as :
A(g) + B(g)⇌C(g)+D(g)
Reaction quotient(Q)=[Cgas][Dgas][Agas][Bgas]
A or B is added i.e concentration of either of reactants is increased then the reaction quotient (Q) decreases i.e Q becomes less than equilibrium constant Keq or Q<Keq.
Hence, equilibrium shifts towards forward direction to nullify the change in concentration.
Case 2: Q becomes more than Keq:
Reaction quotient(Q)=[Cgas][Dgas][Agas][Bgas]
when C or D is added i.e concentration of either of the products is increased then the reaction quotient (Q) increases i.e Q becomes more than equilibrium constant Keq or Q>Keq.
Hence, equilibrium shifts towards backward direction to nullify the change in concentration.
Note :- Addition of a solid or a liquid component to the reaction in small amounts causes no shift in the equilibrium.