CO + 4H --> C3HOH In this reaction , oxygen is added . See the product of reaction. So , this is a oxidation reaction. Why we are calling this as reduction reaction still? See video at 6 : 30
I'm not sure if my explanation is right but i think it is reduction reaction because CO already had an O to it. In the product, O is still present. it is neither added nor removed. It has been there since the start. While H is added to CO in the product. The addition of H is a reduction reaction. I hope this helps :))
