Question

In the reaction 2CO (g) + O2 (g) → 2CO2 (g), what is the ratio of moles of oxygen used to moles of CO2 produced?

Answer 1

For every mole of oxygen consumed, twice as many moles of carbon dioxide are produced.

Answer 2

Yes the ratio is 1:2
For every mole of oxygen, 2 moles of carbon dioxide is used as ghuczek mentioned to you.