Question

which of the following reactions are decomposition reactions?
□ naoh + hcl → hoh + nacl
□ nacl → na + cl₂
□ na + cl₂ → nacl
□ h₂ + o₂ → h₂o
□ ch₄ + o₂ → h₂o + co₂
□ h₂o → h₂ + o₂

Explanation:

A decomposition reaction is a type of chemical reaction where a single compound breaks down into two or more simpler substances. In the given reactions, $\mathrm{NaCl}
ightarrow\mathrm{Na}+\mathrm{Cl}_{2}$ and $\mathrm{H}_{2}\mathrm{O}
ightarrow\mathrm{H}_{2}+\mathrm{O}_{2}$ are decomposition reactions as they involve a single - reactant breaking down into multiple products. The first reaction is $\mathrm{NaOH}+\mathrm{HCl}
ightarrow\mathrm{HOH}+\mathrm{NaCl}$, which is a neutralization reaction. The third reaction $\mathrm{Na}+\mathrm{Cl}_{2}
ightarrow\mathrm{NaCl}$ and the fourth reaction $\mathrm{H}_{2}+\mathrm{O}_{2}
ightarrow\mathrm{H}_{2}\mathrm{O}$ are combination reactions. The fifth reaction $\mathrm{CH}_{4}+\mathrm{O}_{2}
ightarrow\mathrm{H}_{2}\mathrm{O}+\mathrm{CO}_{2}$ is a combustion reaction.

Answer:

$\mathrm{NaCl}
ightarrow\mathrm{Na}+\mathrm{Cl}_{2}$, $\mathrm{H}_{2}\mathrm{O}
ightarrow\mathrm{H}_{2}+\mathrm{O}_{2}$