Which of the following is combustion reactions ?

Options

A. `C+O_(2)rarrCO_(2)`
B. `CH_(4)+O_(2)rarrCO_(2)+H_(2)O`
C. `Mg+O_(2)rarrMgO`
D. All of these

Answer

B

Explanation

When all substances in a compound combine with oxygen and produces `CO_(2)` and `H_(2)O`, it is commonly called burning.
During combustion substance reacts with an oxidising agent such as `O_(2)` and `F_(2)`. Not all combustion reaction releases `CO_(2)` and `H_(2)O` e.g. `Mg+O_(2)rarrMgO+` Heat. `therefore 3.2"gm will liberate = "(890xx3.2)/(16)=178 kJ`.