Question

Any help would be greatly appreciated!

Substances A, B, and C can all act as oxidizing agents. In solution, A is green, B is yellow, and C is red. In the reactions in which they participate, they are reduced to A-, B-, and C- ions, all of which are colorless. When a solution of C is mixed with one containing B- ions, the color changes from red to yellow.
Which species is oxidized? Which is reduced?

When a solution of C is mixed with one containing A- ions, the color remains red.
Is C a better oxidizing agent than A?
Is C a better oxidizing agent than B?

Arrange A B and C in order of increasing strength as an oxidizing agent.

Answer 1

C + B^- ==> C^- + B
You know B^- us colorless and it turns yellow which is the color of B. So the reaction is as I wrote above.
C gains electrons in going to C^- so it is reduced. B^- loses electrons in going to B. It is oxidized.

C+ A^- ==> stays red which means no reaction.

So we have these reactions.
C + A^- ==> N.R.
C + B^- ==> C^- + B

What is an oxidizing agent? That is the gain of electrons is the substance reduced which makes it the oxidizing agent. So C ==> C^- is the gain of electrons which means those reactions above shows which is the stronger oxidizing agent.
C reacts with B^- which means C is a better oxidizing agent than B.
C does not react with A^- which means that A is a stronger oxidizing agent than C.
I would rank these as A, C, B.