Compounds of boron and hydrogen are remarkable for their unusual bonding and also for their reactivity. With the more reactive halogens, for example, diborane (B2H6) forms trihalides even at low temperatures:
B2H6(g) + 6Cl2 (g) --> 2 BCl3 (g) + 6 HCl(g)
H(rxn)= -755.4 kJ
How much heat is released when 4.349 kg of diborane reacts?