Photochemical equivalence law
Let's define an ionic and covalent bond.
An ionic bond occurs between a metal and non-metal. These electrons are transferred between atoms. A Covalent bond occurs between a nonmetal and a nonmetal. These electrons are shared between atoms.
First, identify whether each element is metal or nonmetal. If you need a little help, refer to an online periodic table for guidance.
We see that both Hydrogen and Sulfur are nonmetals. That eliminates both choice 1 and 3.
Then, understanding that within covalent bonds, electrons are shared, choice 4 is eliminated.
Thus, the answer is 2.
A. Burning a match because it changes its form
Hope this really truly helps
