Which of the following is a decomposition reaction? a bao + h2o → ba(oh)2 b ch4 + o2 → co2 + h2o c cao + co2 → caco3 d pbco3 → pbo + co2

The correct answer is D) PbCO3 → PbO + CO2

The way I like to remember synthesis and decomposition is like this:

Synthesis = A + B (Arrow) C

Decomposition = A (Arrow) B + C

Neither = A + B (Arrow) C + D or A (Arrow) B + C (Arrow) D

The correct option is d.

Explanation: Decomposition reactions are the chemical reactions and are defined as the reactions in which a larger molecule breaks down into two or more smaller molecules.

General equation for this chemical reaction:

From the given options above, only one option corresponds to this which is option d.

Option a is a type of combination reaction.

Option b is a type of combustion reaction.

Option c is also a type of combination reaction.

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.