P4 + HNO3 = H3PO4 + NO2 + H20 by partial method balancing

Answer 1

So, first step: decide on the partial equations.

There's a good discussion here:

http://chem-guide.blogspot.com/2010/03/balancing-chemical-equations.html

Answer 2

P4 + HNO3 ---------> H3PO4 + NO +H2O
-> P4 + H2O -> H3PO4
Then using hit and trial method
P4 + H2O -> 4H3PO4 + 10[O]
(addition of 10 atoms of oxygen i.e. nascent oxygen to make the equation balanced)
-> HNO3 -> NO2 + H2O
Again using hit and trial method
2HNO3 +[O] -> 2NO2 + H2O
(addition of 1 atom of nascent oxygen to make the equation balanced)
NOTE : THE SAME EXTRA ATOM HAS TO BE MULTIPLIED ON BOTH THE SIDES AS PER THE SITUATION AND MUST BE CUT AT LAST
Now adding both the equations to make a single balanced equation
P4 + H2O -> 4H3PO4 + 10[O]
+ 2HNO3 +[O] -> 2NO2 + H2O } ×10
————————————————————
P4 + 20HNO3 -> 4H3PO4 + 2NO + 9H2O
AT last the oxygens and 1 water molecule get cancelled and the above answer remains
Hence done......=)

Answer 3

This answer is wrong