Question

Describe how oxidation and reduction involve electrons, change oxidation numbers, and combine in oxidation reduction reactions

Answer 1

Answer: Oxidation is defined as the reaction in which there is loss of electrons. It is accompanied by increase in oxidation number.

$Zn\rightarrow Zn^{2+}+2e^{-}$

Zinc in solid state has oxidation number of zero and on losing electrons changes to $Zn^{2+}$ with oxidation number of +2.

Reduction is defined as the reaction in which there is gain of electrons. It  is accompanied by decrease in oxidation number.

$2H^++e^{-}\rightarrow H_2$

Hydrogen ions with +1 oxidation state gains electrons and converts to molecular hydrogen with oxidation state of zero.

In the given redox reaction, both oxidation and reduction takes place. They go hand in hand.

$Zn+H_2SO_4\rightarrow ZnSO_4 +H_2$

Zinc converts to $Zn^{2+}$ and gets oxidized. $H^+$ gains electron and convert to $H_2$.