Question

which of the following equations represent a single replacement reaction? (multiple answers. choose all that apply)
na(s) + hcl(l) → h₂(g) + nacl(aq)
be(oh)₂(s) → beo(s) + co₂(g)
agno₃(aq) + ki(aq) → agi(s) + kno₃(aq)
h₂(g) + cl₂(g) → 2 hcl(l)
kbr(aq) + cl₂(g) → kcl(aq) + br₂(l)

Explanation:

Step1: Recall single - replacement reaction definition

A single - replacement reaction has the form \(A + BC
ightarrow AC + B\) (where \(A\) is a metal and \(B\) is a metal in \(BC\)) or \(A+BC
ightarrow BA + C\) (where \(A\) is a non - metal and \(C\) is a non - metal in \(BC\)).

Step2: Analyze each equation

• For \(Na(s)+HCl(l)

ightarrow H_{2}(g)+NaCl(aq)\):

• Sodium (\(Na\)) replaces hydrogen (\(H\)) in \(HCl\). The general form \(A + BC

ightarrow AC + B\) (here \(A = Na\), \(B = H\), \(C=Cl\)) is followed.

• For \(Be(OH)_{2}(s)

ightarrow BeO(s)+CO_{2}(g)\):

• This is a decomposition reaction (\(AB

ightarrow A + B\)), not a single - replacement reaction.

• For \(AgNO_{3}(aq)+KI(aq)

ightarrow AgI(s)+KNO_{3}(aq)\):

• This is a double - replacement reaction (\(AB+CD

ightarrow AD + CB\)).

• For \(H_{2}(g)+Cl_{2}(g)

ightarrow 2HCl(l)\):

• This is a combination reaction (\(A + B

ightarrow AB\)).

• For \(KBr(aq)+Cl_{2}(g)

ightarrow KCl(aq)+Br_{2}(l)\):

• Chlorine (\(Cl_{2}\)) replaces bromine (\(Br\)) in \(KBr\). The general form \(A+BC

ightarrow BA + C\) (here \(A = Cl_{2}\), \(B = K\), \(C = Br\)) is followed.

Answer:

\(Na(s)+HCl(l)
ightarrow H_{2}(g)+NaCl(aq)\) and \(KBr(aq)+Cl_{2}(g)
ightarrow KCl(aq)+Br_{2}(l)\)