Question

Fill in the blank with the choices given in the bracket.

_______ ($\mathrm{AgCl}/{\mathrm{PbCl}}_2$), a white precipitate is soluble in excess ${\mathrm{NH}}_4\mathrm{OH}$.

Answer 1

$\mathrm{AgCl}$, a white precipitate is soluble in excess NH₄OH.

When silver chloride ($\mathrm{AgCl}$) reacts with ammonium hydroxide (${\mathrm{NH}}_4\mathrm{OH}$) in excess, it dissolves and forms diammine silver chloride. The reaction is given below :

$\mathrm{AgCl}+2{\mathrm{NH}}_4\mathrm{OH}\to \left[\mathrm{Ag}{\left({\mathrm{NH}}_3\right)}_2\right]\mathrm{Cl}+2{\mathrm{H}}_2\mathrm{O}$
(Silver (Ammonium (Diammine silver (Water)
chloride) hydroxide) chloride)
white ppt.

Whereas lead(II) chloride (${\mathrm{PbCl}}_2$) when reacts with ammonium hydroxide (${\mathrm{NH}}_4\mathrm{OH}$) it gives a chalky white precipitate of lead(II) hydroxide ($\mathrm{Pb}{\left(\mathrm{OH}\right)}_2$) which is insoluble in excess ammonium hydroxide (${\mathrm{NH}}_4\mathrm{OH}$).