A2 + B2 2AB. f H = โ€”200 kJ molโ€“1 AB, A2 and B2 are diatomic molecules. If the bond enthalpies of A2 , B2 and AB are in the ratio 1 : 0.5 : 1, then the bond enth | JEE Mains Chemistry Past Papers โ€” Chem-Mantra | Chem-Mantra