Electric charge on 1gm ion of N^3– is

$$\begin{gathered} Charge on a \sin gle N^{3-} ion = 3\times 1.6\times {10}^{-19}\text{ coluomb } \\ \text{Thus, charge on one g-ion of N3-} \\ =3\times 1.6\times {10}^{-19}\times 6.02\times {10}^{23}=2.89\times {10}^{5}coulomb \end{gathered}$$

Therefore, the correct option is D