Question

are all comproportionation reactions are redox reactions?

Answer 1

Read the question as disproportionation reaction.

Yes. All disproportionation reactions are redox reaction. Because disproportionation reaction means one molecule gets oxidised and another molecule gets reduced. So there is change in oxidation number occurs.( Increase in oxidation number is oxidation and decrease in oxidation number is reduction). For ex.,
$$\begin{gathered} 2C{u}^{+}\to Cu+C{u}^{2+} \\ TheoxidationnoofCuinleftsideis+1.Intherightsideits0and+2. \\ Sointhereaction \\ C{u}^{+}\to Cu,theoxidationnumberischangedfrom+1to0.Thusitgetsreduced. \\ Inthereaction \\ C{u}^{+}\to Cu,theoxidationnumberischangedfrom+1to+2.Thusitgetsoxidised. \\ Sothedisproportionationreactionsareredoxreactions. \end{gathered}$$