Question

If the formula of the nitride of a metal X is XN, what is the formula of:

Its hydroxide.

Answer 1

• From the formula of metal nitride,$\mathrm{XN}$, we find that charge of $\mathrm{X}$ is +3 as the charge of nitride is -3.
• Both balance each other to form the formula$\mathrm{XN}$.
• For example, $\mathrm{AlN}$, etc.
• Now, we know that the charge of hydroxide(${\mathrm{OH}}^{-}$) is -1 and the charge on metal $\mathrm{X}$ is +3.
• By applying the criss-cross method, the formula will be $\mathrm{X}{\left(\mathrm{OH}\right)}_3$.

$$\begin{gathered} \mathrm{Symbol}\mathrm{X}\mathrm{OH} \\ \mathrm{Valency}3\nearrow \nwarrow 1 \end{gathered}$$

Therefore, the formula of metal hydroxide is $\mathrm{X}{\left(\mathrm{OH}\right)}_3$.