Paragraph: When a metal rod $M$ is dipped into an aqueous colourless concentrated solution of compound…
Paragraph:
When a metal rod $M$ is dipped into an aqueous colourless concentrated solution of compound $\mathrm{N}$, the solution turns light blue. Addition of aqueous $\mathrm{NaCl}$ to the blue solution gives a white precipitate $\mathrm{O}$. Addition of aqueous $\mathrm{NH}_3$ dissolves $\mathrm{O}$ and gives an intense blue solution.
Question:
The compound $N$ is
$\mathrm{AgNO}_3$
$\mathrm{Zn}\left(\mathrm{NO}_3\right)_2$
$\mathrm{Al}\left(\mathrm{NO}_3\right)_3$
$\mathrm{Pb}\left(\mathrm{NO}_3\right)_2$
Solution
The compound $N$ is $\mathrm{AgNO}_3$, explained above.