Answer : The correct option for 1st blank is Decomposition and for 2nd blank is Synthesis.
Explanation :
- Decomposition reaction : This reaction occurs when one bigger molecule decomposes into two or more smaller molecules.
- Synthesis reaction : This reaction occurs when two or more smaller reactants combine to form a single large product.
- Combustion reaction : This reaction occurs when a hydrocarbon molecule react with the oxygen molecule to produce carbon dioxide and water.
- Replacement reaction : This reaction occurs when the more reactive element replaces the less reactive element in a compound.
When potassium nitrate breaks down into potassium oxide, nitrogen, and oxygen that means one bigger molecule decomposes into two or more smaller molecules. So, this an example of a decomposition reaction.
And in the opposite process that means potassium oxide, nitrogen, and oxygen are combined to form potassium nitrate means two or more small reactant combine to form a single large product. So, this an example of synthesis reaction.