(a) Arrange the following inthe order of property indicated for each set : (i) F_2,Cl_2,Br_2, I_2 - Increasing bond dissociation enthalpy . (ii) HF, HCl ,HBr, HI - Decreasing acid strength (iii) NH_3 ,PH_3 , AsH_3, SbH_3, BiH_3 - Decreasing base strength . (b) Write the conditions to maximize the yield toH_2SO_4 by contact process .

(a) Arrange the following inthe order of property indicated for each s

1.	(a) Arrange the following inthe order of property indicated for each set : (i) F_2,Cl_2,Br_2, I_2 - Increasing bond dissociation enthalpy . (ii) HF, HCl ,HBr, HI - Decreasing acid strength (iii) NH_3 ,PH_3 , AsH_3, SbH_3, BiH_3 - Decreasing base strength . (b) Write the conditions to maximize the yield toH_2SO_4 by contact process .
Answer» Solution :(a) (i) Increasing BOND dissociation enthalpy `I_2 lt F_2 lt Br_2 lt Cl_2` (ii) Decreasing acid strength HI > HBR > HCl > HF (iii) Decreasing base strength `NH_3 gt PH_3 gt AsH_3 gt SbH_3 gt BiH_3` (b) Conditions for maximum yield of `H_2SO_4` bycontact process (i) Low temperature - 720 K (ii) High pressure - 2 ATM (iii) Purity of gases (iv) Presence of a CATALYST `Pt//V_2O_3` (v) An excess of `O_2`