Question

Which of the following are decomposition reactions?

A. 2LiOH (s) + CO² (g) --> Li²CO³ (s) + H²O (I)
B. K²CO³ (s) --> K²O (s) + CO² (g)
C. 2SO³ (g) --> 2SO² (g) + O² (g)
D. 2Na (s) + Cl² (g) --> 2NaCl (s)

Answer 1

The 2 decomposition reactions are:

B.
`K_(2)`
`CO_(3)` (s) -->
`K_(2) O` (s) +
`CO_(2)` (g)

C.
`2SO_(3)` (g) -->
`2SO_(2)` (g) +
`O_(2)` (g)

Step-by-step explanation:

Step 1:

A decomposition reaction is one in which a single compound breaks down into two or more products.

Step 2:

Let us examine each reaction if it satisfies the above rule.

A. 2 LiOH +
`CO_(2)` --->
`Li_(2) CO_(3)` +
`H_(2) O`

In this reaction we have 2 reactants giving 2 products. Hence this is not a decomposition reaction.

B.
`K_(2) CO_(3)` --->
`K_(2) O` +
`CO_(2)`

In this reaction a single reactant potassium carbonate gives rise to 2 products Potassium Oxide and carbon-di-oxide. Hence this is a decomposition reaction

C.
`2SO_(3)` --->
`2SO_(2)` +
`O_(2)`

In this reaction a single reactant sulfur tri-oxide gives rise to 2 products sulfur di-oxide and oxygen. Hence this is a decomposition reaction.

D.
`2Na` +
`Cl_(2)` --->
`2NaCl_{}`

In this reaction 2 reactants sodium and chlorine gives rise to a single product sodium chloride. Hence this is not a decomposition reaction.

Step 3:

Answer:

The 2 decomposition reactions are:

B.
`K_(2) CO_(3)` (s) --->
`K_(2)O` (s) +
`CO_(2)` (g)

C.
`2SO_(3)` --->
`2SO_(2)` +
`O_(2)`