[Borek]

Are nitric acid and nitrous acid oxidizing agent(oxidzer) or reducing agent(reductor)?

They are reductants.

No. Nitric acid is a strong oxidizer.

I suppose now you know enough to get back to the original question. Don't be so passive. We are pointing you to important facts, and you know enough to answer the original problem, but you stay where you are waiting to be pushed.

[T]

I suppose now you know enough to get back to the original question. Don't be so passive. We are pointing you to important facts, and you know enough to answer the original problem, but you stay where you are waiting to be pushed.

A SnCl2 -- Can be oxidised, Sn 2+  4+ and Cl 1- Cl2

B KI -- Can be oxidised I 1- 12

C CH3CH2OH -- Can be oxidised CH3CH2OH CH3CH2O

D NaNO2 -- Can be oxidised from NO2  NO3

No. Nitric acid is a strong oxidizer.

Is the redox reaction NO₃^- + 2H⁺ + e^- NO₂ + H₂O?

E Al2(SO4)3

This shows that A, B, C, and D can all be oxidised so it can all reduce the dichromate ion. This leaves E as the answer. Can someone just check if my reasoning is correct? Also, will B be the one with the murky brown because of the Iodide?

Thanks

[AWK]

OK

[T]

OK

Does that mean my reasoning is correct?

[AWK]

As I told at beginning, the oxidation numbers are keys to this problem
SnCl2 +2, -1 => +4, 0(Cl2, even more with other oxidizers)
KI;  I -1 => 0 (I2, up to +7)
C2H6O; C -2 (mean value) => up to +4(in CO2)
NaNO2; N +3 => up to +5 (in NO3-)
no ON change in E
Every periodic table contains typical oxidation numbers for all elements.
K, Na, Al, S, H, O - no change in ONs
Note C - ONs for C and H are very close. We always use +1 for H in organic compounds.
If you are familiar with ONs and periodic table the  solution needs less than 1 minute.

[T]

I see, thank you very much

[Borek]

Is the redox reaction NO₃^- + 2H⁺ + e^- NO₂ + H₂O

One of possibilities, yes.