15. This base can be used in fighting certain types of fires because at high temperatures it turns into carbon dioxide, which smothers flames by obstructing the flow of oxygen to the fire. What base is it?

Calcium carbonate (CaCO3)

Explanation:

Calcium carbonate is a solid base. It is known to decompose at high temperature giving out carbon dioxide as follows;

CaCO3(s)> CaO(s) + CO2(g)

The carbon dioxide gas produced is very useful in fire fighting because it smoothers flames.

This reaction only occurs at very high temperature, when a lot of heat has been applied to the system. Hence CaCO3 is a base that can be used in fighting certain kinds of fires.