Which of the following reactions have same heat of reaction at constant pressure and at constant volume?

Which of the following reactions have same heat of reaction at constan

1.	Which of the following reactions have same heat of reaction at constant pressure and at constant volume?
Answer» `H_(2(g)) + Cl_(2(g)) hArr 2HCl_((g))` `2NO_((g)) hArr N_(2(g)) + O_(2(g))` `Co_(3) O_(4(s)) + 4CO_((g)) hArr 3Co_((s)) + 4CO_(2(g))` `N_(2(g)) + 3H_(2(g)) hArr 2NH_(3(g))` Solution :`Delta H = Delta U rArr Delta n_(g) = 0`