Answer
See the answer below.
Work Step by Step
a) BrO, Br is from group 17 and has 7 valence electrons, O is from group 16 and has 6, hydrogen has 1. BrO has 13 valence electrons.
b) First reaction:
1 Br-Br bond broken: $\Delta H= +193\ kJ/mol$
Second reaction:
1 O=O bond broken, 2 Br-O formed:
$\Delta H= 498-2×201=+96\ kJ/mol$
Third reaction:
1 O-H bond broken, 1 H-O formed:
$\Delta H= 0\ kJ/mol$
c) $1/2\ H_2(g)+1/2\ O_2(g)+\ 1/2\ Br_2(g)\rightarrow HOBr(g)$
Bonds broken 1/2 H-H, 1/2 O=O, 1/2 Br-Br
Bonds formed 1 O-H, 1 O-Br
$1/2×(436+498+193)-463-201=-100.5\ kJ/mol$
d) In b, endothermic (the third is neither), in c exothermic.
