Question

Which among the following is not a redox reaction ?
A) 2Na+02 → Na202
B) SO2 + 2H2S → 2H2O +3S
C) Na, O + 2HCl → 2NaCI+H,O
D) MnO, +4HCI → MnCl2 + Cl2 + H2O​

Answer 1

Answer:

(c) option is not redox reaction

Answer 2

The correct option is C) Na2O + 2HCl → 2NaCI+H2O.

• Redox reactions are those in which oxidation and reduction of elements occur simultaneously.
• Oxidation causes the loss of electrons so, there is an increase in the oxidation state.
• Reduction causes gain of electron so, there is a decrease in oxidation state.
• In reaction Na2O + 2HCl, → 2NaCI+H2O oxidation state of Na is +1 before and 2 after reaction but the oxidation state of chlorine is the same -2. so, this reaction is not a redox reaction.
• SO2 + 2H2S → 2H2O +3S is a redox reaction because sulphur in +4 and +2 changed to a 0 oxidation state. so, there is both decreases and increase in the oxidation state.
• MnO, +4HCI → MnCl2 + Cl2 + H2O is a redox reaction because the oxidation state of oxygen is -1 changed to -2 and the oxidation state of Mn changed from +1 to +2.
• 2Na+02 → Na202 is also a redox reaction as sodium oxidation state changed from 0 to +2 and oxygen from 0 to -2.