Mg + HNO3 -----> Mg(NO3)2 + N2O + H2O
Balance this equation by ion-electron method only
Answers
Explanation:
Dear Student,
Please find below the solution to the asked query:
Mg +HNO3 → Mg(NO3)2 +N2O + H2O
To balance this equation by electron ion method
Step1: We write the redox equation in ionic form
Mg + H+ + NO3- → Mg 2+ + N2O + H2O
Step 2 : The reaction is splitted into oxidation half and reduction half reaction
Mg → Mg 2+
NO3- → N2O
Step 3: We balance the atoms of each half reaction except H and O using simple multiples
Mg → Mg 2+
2NO3- → N2O
Step 4:Balancing of H and O
1) For acidic and neutral solutions : H2O is added on the side deficient in O and H+ is added on the side deficient in H+
2) For basic: For each excess O , one H2O is added on the same side and OH- ion to the other side to balance H
Here
H+ is added on the side deficient in H+ and H2O is added on the side deficient in O
Mg → Mg 2+
10 H+ + 2NO3- → N2O + 5H2O
Step 5: Electrons are added to the sides where electrons are deficient
Mg → Mg 2+ +2e [Change in oxidation state Mg → Mg 2 +is 2]
8e + 10 H+ + 2NO3- → N2O + 5H2O [ Change in oxidation state 2HNO3 → N2O is 10-2 =8]
Step 6: The no.of electrons in both equations are equalised
[ Mg → Mg 2+ +2e ] x 4
[ 8e + 10 H+ + 2NO3- → N2O + 5H2O] x1
Step 7: The two balanced half reactions are added and the common terms are cancelled
4 Mg → 4 Mg 2+ + 8e
8e + 10 H+ + 2NO3- → N2O + 5H2O
Adding we get
4 Mg + 10 H+ + 2NO3- → 4 Mg 2+ + N2O + 5H2O
Step 8: Converting the ionic equation into molecular equation and adding the spectator ions we get
4 Mg + 10 H+ + 2NO3- + 8 NO3- → 4 Mg 2+ + N2O + 5H2O + 8NO3-[NO3- is the spectator ion here which is added on both sides of the equation]
Therefore we get: 4 Mg + 10HNO3 → 4 Mg(NO3)2 +N2O + 5H2O
Hope this information will clear your doubts about the topic.
If you have any more doubts just ask here on the forum and our experts will try to help you out as soon as possible.
Regards