Which of the following reactions doesn't represent an oxidation-reduction Which of the following reactions doesn't represent an oxidation-reduction?
$$
  \begin{align*}
    \ce{2 P + 5 HClO + 3 H2O &amp;-&gt; 2 H3PO4 + 5 HCl} \\
    \ce{Zn + 2 HCl &amp;-&gt; ZnCl2 + H2} \\
    \ce{Mg + CuSO4 &amp;-&gt; MgSO4 + Cu} \\
    \ce{NaOH + HNO3 &amp;-&gt; NaNO3 + H2O}
  \end{align*}
$$

I want to find which of those reactions is not an oxidation-reduction reaction, but I'm not sure how to do this and how to find the oxidation numbers, should I memorize them?
Is there some rules like when bases and acids react this can't be an oxidation-reduction reaction — the last reaction implies this — so I can know if the reaction is an oxidation-reduction reaction or not when I look at it without searching for every oxidation number?
If there is an element in the reactants and it is not an element in the products then yes, oxidation or reduction has occurred.
Acid-base reactions are pretty much non-redox reactions. But it is always handy to learn the oxidations numbers.
Extra sources
Do non-redox reactions exist?