Question

Consider the following reaction: `CO_2(g) + H_2(g) -> CO(g) + H_2O(l)` What is being oxidized?

Answer 1

The hydrogen is oxidized.

Explanation:

Even without going into the valency electrons etc., it is clear that the `CO_2` loses one oxygen atom in favour of `H_2O`.
So the `CO_2` is reduced (=oxidator) and the `H_2O` is oxidized (=reductor).