posted by Derrick on .
Which of the following are redox reactions?
(a) Ba(NO3)2 (aq) + H2SO4 (aq) -> BaSO4 (s) + 2 HNO3 (aq)
(b) NH4NO2 (s) -> N2 (g) + 2 H2O (g)
(c) CuO (s) + H2 (g) -> Cu (s) + H2O (L)
How can you tell? Look at the oxidation state of the elements and compare oxidn state on the left with the oxdn state on the right. If they change it is a redox equation. If not it is not a redox equation. I'll do the first one.
Ba is +2 to +2
N is +5 to +5
O is -2 to -2
H is +1 to +1
S is +6 to +6
So nothing changed which makes a) not a redox. Here is a site that will help you assign oxidation states to the elements.