Which equation is a decomposition reaction?
li2co3 --li2o + co2
zn + hcl -- zncl2 + h2
na2o + co2 -- na2co3
c6h12o6 + o2 --co2 + h2o

Explanation:

Decomposition is a type of chemical reaction in which one reactant gives two or more than two products.

1. is an example of decomposition.

2. is an example of single replacement reaction in which more reactive element displaces the less reactive element from its salt solution.

3. is an example of synthesis reaction in which two reactants are combining to form one product.

4. is an example of combustion in which fuel is reacted with oxygen to form carbon dioxide and water.