Question

State the colour of the residue obtained when hot lead carbonate is cooling:
A. White
B. Blue
C. Green
D. Yellow

Answer 1

Lead Carbonate is a type of water-insoluble lead that can readily be converted by heating to other lead compounds, such as oxide. When processed with diluted acids, carbonate compounds also emit carbon dioxide.

Complete step by step answer:
While heated, all-metal carbonates decompose. Some metal carbonates are more reactive than others. Lead is comparatively a less reactive metal carbonate.
This question deals with the chemical reaction involved during the conversion of lead carbonate.
So, let us look into the chemical reaction first;
$\,PbC{O_3} + Heat \to PbO + C{O_2}\,\,$
Lead carbonate is a white coloured powder when heated it forms a red coloured residue. This residue is called litharge or lead monoxide which is lead $\,(II)\,$oxide. But when cooled, this changes its colour to yellow.
Also, a colourless and odourless gas is formed here, which is the carbon dioxide as the by-product. When we pass this through lime water it turns milky.

Compound	Colour before heating	Colour after heating	Colour after cooling	By-product	Decomposition
Lead carbonate	White	Red	Yellow	Carbon dioxide	Easily decompose

So, for this question, the answer is option D, which is Yellow colour .

Note:
In the case of carbonates, It may be fitting to refer to the polarisation of the carbonate ion-electron cloud by the metal ion, and to the fact that this is bound to be more pronounced when the metal ion is double, rather than single, and thin. Eventually, polarisation contributes to the elimination of oxygen from the carbonate ion, creating an oxide ion and a molecule of carbon dioxide. The higher the polarisation, the lower the temperature required for the carbonate to decompose.