What is change in oxidation number of nitrogen when $\mathrm{NO}_3^{-}$is converted to $\mathrm{NH}_4^{+}$ion?

What type of hybridization is present in $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+}$ complex?

For a reaction $\mathrm{r}=\mathrm{k}[\mathrm{A}][\mathrm{B}]^2$, if concentration of $A$ is doubled the rate of reaction

The correct zwitter ion structure of glycine is