To determine which reactions are single displacement reactions, we need to review the definition of a single displacement reaction. In a single displacement (or single replacement) reaction, an element reacts with a compound and takes the place of another element in that compound. The general form of a single displacement reaction is [tex]\( A + BC \rightarrow AC + B \)[/tex], where [tex]\( A \)[/tex] displaces [tex]\( B \)[/tex] in the compound [tex]\( BC \)[/tex].
Let's analyze each of the given reactions:
1. [tex]\[ 2 NaBr + CaF_2 \rightarrow 2 NaF + CaBr_2 \][/tex]
- In this reaction, sodium bromide ([tex]\( NaBr \)[/tex]) reacts with calcium fluoride ([tex]\( CaF_2 \)[/tex]), resulting in the formation of sodium fluoride ([tex]\( NaF \)[/tex]) and calcium bromide ([tex]\( CaBr_2 \)[/tex]). Here, [tex]\( Na \)[/tex] and [tex]\( Ca \)[/tex] effectively swap places.
- This fits the format of a double displacement reaction, not a single displacement reaction.
2. [tex]\[ SnO_2 + 2 H_2 \rightarrow Sn + 2 H_2O \][/tex]
- In this reaction, tin(IV) oxide ([tex]\( SnO_2 \)[/tex]) reacts with hydrogen gas ([tex]\( H_2 \)[/tex]), producing tin ([tex]\( Sn \)[/tex]) and water ([tex]\( H_2O \)[/tex]). Here, hydrogen displaces tin in the oxide.
- This is a single displacement reaction.
3. [tex]\[ 4 Na + O_2 \rightarrow 2 Na_2O \][/tex]
- In this reaction, sodium ([tex]\( Na \)[/tex]) reacts with oxygen ([tex]\( O_2 \)[/tex]), producing sodium oxide ([tex]\( Na_2O \)[/tex]). This is a combination reaction (or synthesis reaction) and not a single displacement reaction.
4. [tex]\[ 2 KClO_3 \rightarrow 2 KCl + 3 O_2 \][/tex]
- In this reaction, potassium chlorate ([tex]\( KClO_3 \)[/tex]) decomposes into potassium chloride ([tex]\( KCl \)[/tex]) and oxygen gas ([tex]\( O_2 \)[/tex]). This is a decomposition reaction, not a single displacement reaction.
5. [tex]\[ 2 Al + 6 HCl \rightarrow 2 AlCl_3 + 3 H_2 \][/tex]
- In this reaction, aluminum ([tex]\( Al \)[/tex]) reacts with hydrochloric acid ([tex]\( HCl \)[/tex]), forming aluminum chloride ([tex]\( AlCl_3 \)[/tex]) and hydrogen gas ([tex]\( H_2 \)[/tex]). Here, aluminum displaces hydrogen in the hydrochloric acid.
- This is a single displacement reaction.
So, the single displacement reactions among the given options are:
- [tex]\( SnO_2 + 2 H_2 \rightarrow Sn + 2 H_2O \)[/tex]
- [tex]\( 2 Al + 6 HCl \rightarrow 2 AlCl_3 + 3 H_2 \)[/tex]
Thus, the correct answers are:
- [tex]\( SnO_2 + 2 H_2 \rightarrow Sn + 2 H_2O \)[/tex]
- [tex]\( 2 Al + 6 HCl \rightarrow 2 AlCl_3 + 3 H_2 \)[/tex]
