Arrange the following in the order or property indicated for each set
(a) `F_2, Cl_2, Br_2, I_2` Increasing bond dissociation enthalpy.
(b) HF, HCI, HBr, HI Increasing acid strength.
(c ) `NH_3 ,PH_3 , AsH_3 , SbH_3, BiH_3` Increasing base strength.

Explanation

(a) `I_2 lt F_2 lt Br_2 lt Cl-2`
(b) HF < HCl < HBr < HI
(c) `BiH_3 lt SbH_3 lt AsH_3 lt PH_3 lt NH_3`
This is because bond energy increases.