The table shows the number of reactants and products present during two separate chemical reactions.

chemical change comparison
chemical reaction reactants products
a 1 3
b 2 1

which of the following statements correctly identifies the decomposition reaction and describes a substance involved?
chemical reaction a, because the reactant is a compound
chemical reaction b, because the product is a compound
chemical reaction a, because the reactant is an element
chemical reaction b, because the product is an element

Option (a) is the correct answer.

Explanation:

A decomposition reaction is defined as a reaction where a compound dissociates into two or more atoms.

For example,

Whereas a chemical reaction in which two reactants combine together to result in the formation of a compound is known as a synthesis reaction.

For example, is a synthesis reaction.

Thus, we can conclude that the statement chemical reaction A, because the reactant is a compound identifies the decomposition reaction and describes a substance is involved.

- decrease the number of plants and animals living in the water.