A:H2SO4(aq)+BaCl2(aq)=2HCl(aq)+BaSO4(s);△H<0
B:CH3CH2OH(l)+3O2(g) 2CO2(g)+3H2O(l) ;△H<0
C:4Fe(OH)2(s)+2H2O(l)+O2(g)=4Fe(OH)3(s) ;△H<0
D:3Cu(s)+8HNO3(aq)=3Cu(NO3)2(aq)+2NO(g)+4H2O(l) ;△H<0