27.6 gm of silver carbonate on strong ignition leaves a residue weighing

$A{g}_{2}C{O}_3\to 2Ag+C{O}_2+\frac{1}{2}{O}_2$

               276 gm Ag₂CO₃ $\to$  2 x 108 gm Ag (Residue)

               27.6 gm Ag₂ CO₃ $\to$ ?

                                                                   $=2\times 10.8=21.6gm$