Some Basic Concepts of Chemistry - Result Question 13
28. 2.76 g of silver carbonate on being strongly heated yields a residue weighing
(1979, 1M)
(a) 2.16 g
(b) 2.48 g
(c) 2.32 g
(d) 2.64 g
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Answer:
Correct Answer: 28. (a)
Solution:
- Unlike other metal carbonates that usually decomposes into metal oxides liberating carbon dioxide, silver carbonate on heating decomposes into elemental silver liberating mixture of carbon dioxide and oxygen gas as :
$\begin{array}{cc} \mathrm{Ag}_2 \mathrm{CO}_3(s) \xrightarrow{\text { Heat }} & 2 \mathrm{Ag}(\mathrm{s})+\mathrm{CO}_2(\mathrm{~g})+\frac{1}{2} \mathrm{O}_2(\mathrm{~g}) \\ \mathrm{MW}=276 \mathrm{~g} & 2 \times 108=216 \mathrm{~g} \end{array}$
Hence, 2.76 g of $\mathrm{Ag}_2 \mathrm{CO}_3$ on heating will give $\frac{216}{276} \times 2.76=2.16 \mathrm{~g} \mathrm{Ag}$ as residue.
BETA
