Final answer:
Nitration is the process of replacing hydrogen by NO₂ in methane.
Step-by-step explanation:
The replacement of hydrogen by NO₂ in methane is called Nitration. In the process of nitration, one or more of the hydrogen atoms in a hydrocarbon are replaced by nitro groups (NO₂). This reaction is commonly used in the synthesis of organic compounds, such as pharmaceuticals and dyes.