Some Basic Concepts of Chemistry - Result Question 90
####28. The difference in the oxidation numbers of the two types of sulphur atoms in $Na _2 S _4 O _6$ is
(2011)
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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 :
$$ \begin{array}{cc} Ag _2 CO _3(s) \stackrel{\text { Heat }}{\longrightarrow} & 2 Ag(s)+CO _2(g)+\frac{1}{2} O _2(g) \ MW=276 g & 2 \times 108=216 g \end{array} $$
Hence, $2.76 g$ of $Ag _2 CO _3$ on heating will give
$$ \frac{216}{276} \times 2.76=2.16 g Ag \text { as residue. } $$
