Question

Consider the binding of oxygen to haemoglobin: $H{b}_{aq}+O_{2\left(g\right)}\rightleftharpoons Hb-O_{\left(aq\right)}.$ If we decrease the pressure of the system, what is the effect on this equilibrium reaction?

• A. The equilibrium shifts to the left
• B. The equilibrium shifts to the right
• C. There is no change in the system
• D. None of the above

Answer 1

The correct option is A The equilibrium shifts to the left

An equilibrium reaction responds to a decrease in pressure by favouring the reaction that produces the most molecules. In this case, the reaction will shift to the left, favouring the dissociation of oxygen from haemoglobin, as this generates more separate molecules than the forward reaction.