Question

Given the partial equation: NO3− Pb2 → NO2 Pb4 , balance the reaction in acidic solution using the half-reaction method and fill in the coefficients. The missing blanks represent H2O, H , or OH-, as required to balance the reaction. Enter the coefficients as integers, using the lowest whole numbers. If the coefficient for something is "1", make sure to type that in and not leave it blank. Enter only the coefficients.

Answer 1

Answer : The balanced reaction in acidic solution is,

$2NO_3^-+1Pb^{2+}+4H^+\rightarrow 2NO_2+1Pb^{4+}+2H_2O$

Explanation :

The given partial equation is,

$NO_3^-+Pb^{2+}\rightarrow NO_2+Pb^{4+}$

First we have to separate into half reaction. The two half reactions are:

$NO_3^-\rightarrow NO_2$

$Pb^{2+}\rightarrow Pb^{4+}$

Now we have to balance the half reactions in acidic medium, we get:

$NO_3^-+2H^++1e^-\rightarrow NO_2+H_2O$       ............(1)

$Pb^{2+}\rightarrow Pb^{4+}+2e^-$     ............(2)

Now we have to balance the electrons of the half reactions. When we are multiplying the equation (1) by 2, we get

$2NO_3^-+4H^++2e^-\rightarrow 2NO_2+2H_2O$  ...........(3)

Now we have to add both the half reactions (2) and (3), we get the final balanced chemical reaction.

$2NO_3^-+1Pb^{2+}+4H^+\rightarrow 2NO_2+1Pb^{4+}+2H_2O$