write the half reactions for 2Li + H2 - 2LiH

Question

write the half reactions for 2Li + H2 -> 2LiH

anonymous · Answer

$$Li \rightarrow Li ^{+} + e ^{-}$$
and
$$H _{2} \rightarrow 2H ^{+} + 2e ^{-}$$

anonymous · Answer

Although this doesn't quite make sense as the electrons of 2 half equations should be on the opposite side of the arrow

anonymous · Answer

Well one is oxidation and the other is reduction, but what happened to the 2 for the Li

anonymous · Answer

Oh sorry, the charge of hydrogen will be 1- as the compound is a metal hydride so
$$H _{2} + 2e^{-} \rightarrow 2H ^{-}$$

anonymous · Answer

Then you just double the half equation for lithium so the number of electrons are the same and will cancel off when you combine the 2 half equations

anonymous · Answer

ah yes, overlooked that as well
so 
2Li + H2 + 2e-  --> 2Li+ + 2H- +2e-
so cancel
2Li + H2 --> 2Li+ + 2H-