Question

A ________ reaction occurs when one compound reacts and is broken down into different elements or simpler compounds?

Answer 1

Answer: decomposition

Explanation:

1 . Combustion is a type of chemical reaction in which a hydrocarbon reacts with oxygen to form carbon dioxide ans water along with liberation of large amount of energy.

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

$CaCO_3\rightarrow CaO+CO_2$

3. Single replacement is a type of chemical reaction in which a more reactive element displaces the less reactive element from its slat solution.

4. Synthesis is a type of chemical reaction in which two or more than two reactants combine together to give a single product.

Answer 2

Answer: The correct answer is decomposition reaction.

Explanation:

For the given options:

Option 1: Combustion

Combustion reaction is defined as the chemical reaction in which a hydrocarbon reacts with oxygen gas to produce carbon dioxide gas and water molecule.

$\text{Hydrocarbon}+O_2\rightarrow CO_2+H_2O$

Option 2: Decomposition

Decomposition reaction is defined as the reaction in which a single large substance breaks down into two or more smaller substances.

$AB\rightarrow A+B$

Option 3: Single replacement

Single replacement reaction is defined as the reaction in which more reactive element displaces a less reactive element from its chemical reaction.

The reactivity of metal is determined by a series known as reactivity series. The metals lying above in the series are more reactive than the metals which lie below in the series.

$A+BC\rightarrow AC+B$

Metal A is more reactive than metal B.

Option 4: Synthesis

Synthesis reaction is defined as the reaction in which smaller substances combine in their elemental state to form a larger substance.

$A+B\rightarrow AB$

Hence, the correct answer is decomposition reaction.