The element which never acts as a reducing agent in a chemical reaction is

While sulphur dioxide and hydrogen peroxide can act as oxidising as well as reducing agents in their reactions,ozone and nitric acid act only as oxidants. Why?

Lithium aluminium hydride $(LiAlH_4)$ acts as:

Which of the following substances acts as both an oxidizing agent and a reducing agent?

Why does the following reaction occur?
$XeO_6^{4-}{(aq)} + 2F^{-}{(aq)} + 6H^{+}{(aq)} \rightarrow XeO_{3_{(g)}} + F_{2_{(g)}} + 3H_2O_{(l)}$
What conclusion about the compound $Na_4XeO_6$ (of which $XeO_6^{4-}$ is a part) can be drawn from the reaction?

Which of the following is an oxidizing agent?