Which gives ${\mathrm{CO}}_2$ on heating slaked lime or limestone?

Slaked lime

• The chemical formula of slaked lime is $\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$.
• Slaked lime (calcium hydroxide) gives Calcium oxide and water on heating.
• The reaction is as follows:-
• $\mathrm{Ca}{\left(\mathrm{OH}\right)}_2\left(\mathrm{aq}\right)\stackrel{∆}{\to }\mathrm{CaO}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$

Limestone

• The chemical formula of limestone is ${\mathrm{CaCO}}_3$
• Limestone (calcium carbonate) gives Calcium oxide and carbon dioxide gas on heating.
• The reaction is as follows:-
• ${\mathrm{CaCO}}_3\left(\mathrm{s}\right)\stackrel{∆}{\to }\mathrm{CaO}\left(\mathrm{s}\right)+{\mathrm{CO}}_2\left(\mathrm{g}\right)$
• Hence, limestone gives ${\mathrm{CO}}_2$ on heating .