Addition of sodium thiosulphate solution to a solution of silver nitrate gives $X$ as white precipitate, insoluble in water but soluble in excess thiosulphate solution to give $Y$. On boiling in water, $Y$ gives $Z . X, Y$ and $Z$ respectively are

• Correct answer
  A

  $\mathrm{Ag}_{2} \mathrm{S}_{2} \mathrm{O}_{3} \cdot \mathrm{Na}_{3}\left[\mathrm{Ag}\left(\mathrm{S}_{2} \mathrm{O}_{3}\right)_{2}\right], \mathrm{Ag}_{2} \mathrm{S}$
• B

  $\mathrm{Ag}_{2} \mathrm{SO}_{4}, \mathrm{Na}\left[\mathrm{Ag}\left(\mathrm{S}_{2} \mathrm{O}_{3}\right)_{2}\right], \mathrm{Ag}_{2} \mathrm{S}_{2}$
• C

  $\mathrm{Ag}_{2} \mathrm{S}_{2} \mathrm{O}_{3} \cdot \mathrm{Na}_{5}\left[\mathrm{Ag}\left(\mathrm{S}_{2} \mathrm{O}_{3}\right)_{3}\right], \mathrm{AgS}$
• D

  $\mathrm{Ag}_{2} \mathrm{SO}_{3} \cdot \mathrm{Na}_{3}\left[\mathrm{Ag}\left(\mathrm{S}_{2} \mathrm{O}_{3}\right)_{2}\right], \mathrm{Ag}_{2} \mathrm{O}$

Solution

The sequence of reactions are Hence, $X=A g_{2} S_{2} O_{3}$ $Y=\mathrm{Na}_{3}\left[\mathrm{Ag}\left(\mathrm{S}_{2} \mathrm{O}_{3}\right)_{2}\right] Z=\mathrm{Ag}_{2} \mathrm{S}$

Hence, the correct answer is option: 'A'.