Question

identify the substances oxidised,reduced,oxidising agent,redusing agent?
1-CuO+2HCL---------->CuCl2+H2O
2-NaOH---------->Na+ + OH-
3-4Al + 3O2

Answer 1

Whenever we have to identify substances which are oxidised, reduced, reducing agent and oxidizing agent, we pick that substance from the left side of the equation i.e. the reactant side.
1) Oxidized- HCl
Reduced- CuO
R.A.- HCl
O.A. - CuO
Try to find out the other two by yourself and if you aren't able to find then ask it in the comment section.