b
(b)\({C_2}{H_4} + 3{O_2} \to 2C{O_2} + 2{H_2}O\)
\(\Delta {H_{{\rm{reaction}}}} = [2 \times \Delta H_f^o(C{O_2}) + 2 \times \Delta H_f^o\,({H_2}O)]\)
\( - [\Delta H_f^o\,({C_2}{H_4}) + \,3\,\, \times \Delta H_f^o\,({O_2})]\)
\( = [\,2\,(\, - 394) + 2\,(\, - 286)] - [52 + 0] = - 1412\,kJ\).