When under certain conditions, the $P_{50}$ value of haemoglobin rises, the affinity of the pigment of combining with $O_2$ will –

The correct option is A Fall
It is well explained by Oxygen dissociation curve.


In the alveoli, where there is high $p{O}_2$, low $pC{O}_2$, lesser $H^{+}$ concentration and lower temperature, the factors are all favourable for the formation of oxyhaemoglobin, whereas in the tissues, where low $p{O}_2$, high $pC{O}_2$, high $H^{+}$ concentration and higher temperature exist, the conditions are favourable for dissociation of oxygen from the
oxyhaemoglobin.
This clearly indicates that $O_2$ gets bound to haemoglobin in the lung surface and gets dissociated at the tissues.