Question

Amoung Nh3 , HNO3 , NAN3 and MG3N2 the number of molecules having nitrogen in negative oxidation state is

Answer 1

Given: Given species are $NH_3, HNO_3, NaN_3, Mg_3N_2$.

To find: We have to find the number of molecules having nitrogen in a negative oxidation state.

Solution:

$NH_3$

The charge of a hydrogen atom is +1.

Let oxidation state of N is x.

The molecule is neutral so, the overall oxidation state is zero.

Thus oxidation state of N is as follows-

x+1×3=0

x=-3

The oxidation state of N is -3.

$HNO_3$

The charge of a hydrogen atom is +1 and the charge of an Oxygen atom is -2.

Let oxidation state of N is x.

The molecule is neutral so, the overall oxidation state is zero.

Thus oxidation state of N is as follows-

x+1+(-2×3)=0

x=+5

The oxidation state of N is +5.

$NaN_3$

The charge of a Na atom is +1.

Let oxidation state of N is x.

The molecule is neutral so, the overall oxidation state is zero.

Thus oxidation state of N is as follows-

3x+1=0

x=-1/3

The oxidation state of N is -1/3.

$Mg_3N_2$

The charge of an Mg atom is +2.

Let oxidation state of N is x.

The molecule is neutral the o, the overall oxidation state is zero.

Thus oxidation state of N is as follows-

2x+3×(+2)=0

x=-3

The oxidation state of N is -3.

3 molecules have nitrogen in a negative oxidation state.