Question

Which of the following is/are example(s) of combination reaction?

• A. ${\text{CH}}_4+2{\text{O}}_2\to {\text{CO}}_2+2{\text{H}}_2\text{O}$
• B. $\text{MgO}+{\text{CO}}_2\to {\text{MgCO}}_3$
• C. $\text{CaO}+{\text{O}}_2\to 2{\text{CaCO}}_3$
• D. $2\text{AgCl}\stackrel{\text{sunlight}}{⟶}2\text{Ag}+{\text{Cl}}_2$

Answer 1

Answer: (B), (C)

$\text{CaO}+{\text{O}}_2\to 2{\text{CaCO}}_3$

In a combination reaction two or more reactants combine to form a single product. The reactions involving formation of magnesium carbonate and calcium carbonate are examples of combination reaction as two reactants are combining to give a single product.

When Methane and Oxygen reacts, the bonds in the methane and oxygen come apart, the atoms rearrange and then re-bond to form water and carbon dioxide. It is an example of combustion reaction.

When silver chloride is exposed to sunlight, decomposition reaction takes place. AgCl is broken down into Ag and Cl.