Respuesta :
Single displacement and combustion reactions are ALWAYS redox.
Answer : The two types of reactions always redox reaction are, Single-displacement reaction and Disproportionation reaction.
Explanation :
Redox reaction or Oxidation-reduction reaction : It is defined as the reaction in which the oxidation and reduction reaction takes place simultaneously.
Single-displacement reaction : It is a type of reaction in which the most reactive element displaces the least reactive element from its compound.
It is type of redox reaction where a species simultaneously oxidized and reduced and form different products.
For example : [tex]Mg+CuSO_4\rightarrow MgSO_4+Cu[/tex]
In this reaction, oxidation takes place when [tex]Mg[/tex] lose electrons and form [tex]Mg^{2+}[/tex] and reduction takes place when [tex]Cu^{2+}[/tex] gain electrons and form [tex]Cu[/tex].
Disproportionation reaction : It is a type of chemical reaction in which a molecule is converted or transformed into two or more different products.
It is type of redox reaction where a species simultaneously oxidized and reduced and form different products.
For example : [tex]2H_2PO_4^-\rightarrow HPO_4^{2-}+H_3PO_4[/tex]
In this reaction, oxidation and reduction reaction takes palace simultaneously by the one species that is, [tex]H_2PO_4^-[/tex].
In this reaction, oxidation takes place when [tex]H_2PO_4^-[/tex] lose electrons and form [tex]HPO_4^{2-}[/tex] and reduction takes place when [tex]H_2PO_4^-[/tex] gain electrons and form [tex]H_3PO_4[/tex].
Hence, the two types of reactions always redox reaction are, Single-displacement reaction and Disproportionation reaction.