Carbon monoxide (co) is toxic because it binds more strongly to the iron in hemoglobin (hb) than does oxygen (o2), as indicated by these approximate standard free-energy changes in blood:

reaction a: reaction b: hb+o2hb+co⟶⟶hbo2,hbco, δg∘=−70 kj/mol δg∘=−80 kj/mol

estimate the equilibrium constant k at 298 k for the equilibrium

hbo2+co⇌hbco+o2

Answer : The value of equilibrium constant K at 298 K is, 56.59

Explanation :

The given chemical reaction are:

(1) ;    

(2) ;    

First we have to determine the standard free-energy change for the following reaction.

(3) ;    

Now we are reversing the reaction 1 and then adding reaction 1 and 2, we get:

(1) ;    

(2) ;    

Now we have to calculate the equilibrium constant K at 298 K.

where,

= standard Gibbs free energy  = -10kJ/mol = -10000 J/mol

R = gas constant = 8.314 J/K.mol

T = temperature = 298 K

 = equilibrium constant  = ?

Now put all the given values in the above formula, we get:

Therefore, the value of equilibrium constant K at 298 K is, 56.59