I have this redox reaction that I can't balance using half reaction method.

$$\ce{Mg + HNO3 -> Mg(NO3)2 + N2O + H2O}$$

What I get at the end is

$$\ce{2Mg + 6HNO3 -> 2Mg(NO3)2 + 3N2O +3H2O}$$

I can't get the $\ce{N}$ balanced.


1 Answer 1


It seems likely that you are starting with the wrong half reactions.

Since this reaction happens in water, separate the ionic species into their ions:

$$\ce{Mg(NO3)2 -> Mg^{2+} + 2NO3-}$$

$$\ce{HNO3 -> H+ + NO3-}$$

Now, one half reaction should involve magnesium (and have no nitrogen anywhere). The other half reaction should involve nitrogen only.

$$\ce{Mg -> Mg^{2+}}$$ $$\ce{NO3- -> N2O}$$


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.