Of the reactions below which one is not a combination reaction? 2ch4+402=2co2+4h20
2mg+o2=2mg0

2Mg + O₂ → 2MgO

Explanation:

Given reaction:

             2Mg + O₂ → 2MgO

This is the only combination reaction from the given set of choices.

A combination reaction is a synthesis reaction.

In this kind of reaction, a single product is formed from two or more reactants.

  E.g

         A + B → C

The formation of a compound from constituent elements falls into this category of reaction.

hope this

explanation:

covalent bonds

consist of pairs of electrons shared by two atoms, and bind the atoms to fixed orientation and requre high energies to break them

ionic bonds

when two atoms differ considerably in their electronegativity, then one of the atoms will lose its electron to the other atom. this results in a positively charged ion(cation) and a negatively charged ion (anion)