Chemistry related question

Question

Balance the equation for the reaction, using no fractional coefficients.

?P+? HNO3 +? H2O -> ? H3PO4 + ? NO

The ratio of the moles of oxidizing agent to moles of reducing agent in the balanced equation is

(A) 5 to 2.

(B) 5 to 3.

(C) 3 to 5.

(D) 2 to 5.

(E)1 to 1.

Answer 1

P + HNO₃ + H₂O ==> H₃PO₄ + NO .. unbalanced

First, identify the oxidizing and reducing agents:

P goes from oxidation number zero to oxidation number 3+ (it was oxidized and is the red. agent)

N goes from oxidation number 5+ to oxidation number 2+ (it was reduced and HNO3 is the ox. agent)

Balance the redox equation (did this using half reactions):

3 P + 5 HNO₃ + 2 H₂O ==> 3 H₃PO₄ + 5 NO .. balanced redox equation

mole ratio of oxidizing agent to reducing agent:

moles oxidizing agent (HNO3) = 5

moles reducing agent (P) = 3

Answer = 5 to 3 = (B)