Use the chemical equation to complete the activity.

H2(g) + I2(g) → 2HI(g)
A student makes the following statements:
Hydrogen always has the same oxidation number, so it has an oxidation number of +1 in both the reactant H2 and product HI.
Iodine is in Group VIIA, so it has an oxidation number of –1 in both the reactant I2 and product HI.
Neither hydrogen nor iodine changes oxidation states, so the reaction is not a redox reaction.
In three to five sentences, describe the mistake that the student made, and determine whether or not the reaction is a redox reaction. Explain your answer.
pls help me with this question i dont know how to work these out thank you!!

2 answers

It would help if you let us know what you don't understand. I suspect you just don't know how to determine oxidation states. Here is a link that will get you to a very good site that explains how you do that.
://www.chemteam.info/ChemTeamIndex.html
You want to click on the oxidation-reduction square. You will see that the oxidation states of both H and I change.
Thank you for not just giving the answer to this question as it comes directly from a chemistry unit test.