Question

types of reactions
chemistry lesson types of chemical reactions
ah→a+b
nh4cl(s)→nh3(g)+hcl(g)
2h2o(l)→2h2(g)+o2(g)
multiple - choice question
which of the following reactions is a decomposition reaction?
si + o2→sio2
2kcl→2k + cl2
2h2 + o2→2h2o
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Explanation:

Step1: Recall decomposition reaction definition

A decomposition reaction is a reaction where a single compound breaks down into two or more simpler substances.

Step2: Analyze each reaction

• For \(2H_2 + O_2

ightarrow2H_2O\), it is a combination reaction (two substances combine to form one).

• For \(2KCl

ightarrow2K + Cl_2\), it is a decomposition reaction (one compound breaks into two elements).

• For \(Si+O_2

ightarrow SiO_2\), it is a combination reaction.

• For \(2H_2O(l)

ightarrow2H_2(g)+O_2(g)\), it is a decomposition reaction (water breaks into hydrogen and oxygen).

• For \(NH_4Cl(s)

ightarrow NH_3(g)+HCl(g)\), it is a decomposition reaction (ammonium chloride breaks into ammonia and hydrogen chloride).

Answer:

\(2H_2O(l)
ightarrow2H_2(g)+O_2(g)\) and \(NH_4Cl(s)
ightarrow NH_3(g)+HCl(g)\) and \(2KCl
ightarrow2K + Cl_2\) are decomposition reactions.