Question

Which of the following is a synthesis reaction?

C2H4 + 3O2 yields 2CO2 + 2H2O

2HBr yields H2 + Br2

CO2 + H2O yields H2CO3

F2 + 2 HCl yields Cl2 + 2HF

Answer 1

CO2 + H2O yields H2CO3 is a synthesis reaction.

Answer 2

Answer: The correct answer is
`CO_2+H_2O\rightarrow H_2CO_3`

Step-by-step explanation:

Synthesis reaction is defined as the reaction in which two or more small substances combine together to form a single large compound. General equation representing this reaction follows:

`A+B\rightarrow AB`

For the given reactions:

Reaction 1:
`C_2H_4+3O_2\rightarrow 2CO_2+2H_2O`

This reaction is considered as a combustion reaction because here, hydrocarbon is reacting with oxygen gas to produce carbon dioxide and water molecule.

Reaction 2:
`2HBr\rightarrow H_2+Br_2`

This reaction is considered as a decomposition reaction because here, one substance is forming two smaller substances.

Reaction 3:
`CO_2+H_2O\rightarrow H_2CO_3`

This reaction is considered as a synthesis reaction because here, two smaller substances are forming one single compound.

Reaction 4:
`F_2+2HCl\rightarrow Cl_2+2HF`

This reaction is considered as a single displacement reaction because here, a more reactive element is displacing a less reactive element.

Hence, the correct answer is
`CO_2+H_2O\rightarrow H_2CO_3`