Answer :
To determine which chemical equation represents a redox reaction, we need to look at changes in oxidation states of the elements involved in each reaction. A redox reaction involves changes in oxidation states, implying that electrons are transferred from one species to another. For simplicity, let's analyze each provided chemical equation:
A. [tex]\( Mg(ClO_3)_2 + 2 HCl \rightarrow MgCl_2 + 2 HClO_3 \)[/tex]
- [tex]\( Mg(ClO_3)_2 \)[/tex]: [tex]\( Mg \)[/tex] has an oxidation state of [tex]\( +2 \)[/tex], [tex]\( Cl \)[/tex] in [tex]\( ClO_3^- \)[/tex] has an oxidation state of [tex]\( +5 \)[/tex].
- [tex]\( HCl \)[/tex]: [tex]\( H \)[/tex] is [tex]\( +1 \)[/tex], and [tex]\( Cl \)[/tex] is [tex]\( -1 \)[/tex].
- [tex]\( MgCl_2 \)[/tex]: [tex]\( Mg \)[/tex] is [tex]\( +2 \)[/tex], [tex]\( Cl \)[/tex] is [tex]\( -1 \)[/tex].
- [tex]\( HClO_3 \)[/tex]: [tex]\( H \)[/tex] is [tex]\( +1 \)[/tex], [tex]\( Cl \)[/tex] in [tex]\( ClO_3 \)[/tex] is [tex]\( +5 \)[/tex].
There are no changes in the oxidation states of any of the elements. Hence, this is not a redox reaction.
B. [tex]\( CO + H_2O \rightarrow H_2 + CO_2 \)[/tex]
- [tex]\( CO \)[/tex]: [tex]\( C \)[/tex] in [tex]\( CO \)[/tex] has an oxidation state of [tex]\( +2 \)[/tex], [tex]\( O \)[/tex] is [tex]\( -2 \)[/tex].
- [tex]\( H_2O \)[/tex]: [tex]\( H \)[/tex] is [tex]\( +1 \)[/tex], [tex]\( O \)[/tex] is [tex]\( -2 \)[/tex].
- [tex]\( H_2 \)[/tex]: [tex]\( H \)[/tex] is [tex]\( 0 \)[/tex].
- [tex]\( CO_2 \)[/tex]: [tex]\( C \)[/tex] in [tex]\( CO_2 \)[/tex] is [tex]\( +4 \)[/tex], [tex]\( O \)[/tex] is [tex]\( -2 \)[/tex].
Here, the oxidation state of [tex]\( C \)[/tex] changes from [tex]\( +2 \)[/tex] in [tex]\( CO \)[/tex] to [tex]\( +4 \)[/tex] in [tex]\( CO_2 \)[/tex], and the oxidation state of [tex]\( H \)[/tex] changes from [tex]\( +1 \)[/tex] in [tex]\( H_2O \)[/tex] to [tex]\( 0 \)[/tex] in [tex]\( H_2 \)[/tex]. Hence, this is a redox reaction.
C. [tex]\( 2 NH_4NO_3 + CuCl_2 \rightarrow 2 NH_4Cl + Cu(NO_3)_2 \)[/tex]
- [tex]\( NH_4NO_3 \)[/tex]: [tex]\( N \)[/tex] in [tex]\( NH_4^+ \)[/tex] is [tex]\( -3 \)[/tex], [tex]\( N \)[/tex] in [tex]\( NO_3^- \)[/tex] is [tex]\( +5 \)[/tex].
- [tex]\( CuCl_2 \)[/tex]: [tex]\( Cu \)[/tex] is [tex]\( +2 \)[/tex], [tex]\( Cl \)[/tex] is [tex]\( -1 \)[/tex].
- [tex]\( NH_4Cl \)[/tex]: [tex]\( N \)[/tex] in [tex]\( NH_4^+ \)[/tex] is [tex]\( -3 \)[/tex], [tex]\( Cl \)[/tex] is [tex]\( -1 \)[/tex].
- [tex]\( Cu(NO_3)_2 \)[/tex]: [tex]\( Cu \)[/tex] is [tex]\( +2 \)[/tex], [tex]\( N \)[/tex] in [tex]\( NO_3^- \)[/tex] is [tex]\( +5 \)[/tex].
There are no changes in the oxidation states of any of the elements. Hence, this is not a redox reaction.
D. [tex]\( Na_2SO_3 + FeBr_2 \rightarrow 2 NaBr + FeSO_3 \)[/tex]
- [tex]\( Na_2SO_3 \)[/tex]: [tex]\( Na \)[/tex] is [tex]\( +1 \)[/tex], [tex]\( S \)[/tex] is [tex]\( +4 \)[/tex], [tex]\( O \)[/tex] is [tex]\( -2 \)[/tex].
- [tex]\( FeBr_2 \)[/tex]: [tex]\( Fe \)[/tex] is [tex]\( +2 \)[/tex], [tex]\( Br \)[/tex] is [tex]\( -1 \)[/tex].
- [tex]\( NaBr \)[/tex]: [tex]\( Na \)[/tex] is [tex]\( +1 \)[/tex], [tex]\( Br \)[/tex] is [tex]\( -1 \)[/tex].
- [tex]\( FeSO_3 \)[/tex]: [tex]\( Fe \)[/tex] is [tex]\( +2 \)[/tex], [tex]\( S \)[/tex] is [tex]\( +4 \)[/tex], [tex]\( O \)[/tex] is [tex]\( -2 \)[/tex].
There are no changes in the oxidation states of any of the elements. Hence, this is not a redox reaction.
Based on the analysis, the chemical equation that represents a redox reaction is:
B. [tex]\( CO + H_2O \rightarrow H_2 + CO_2 \)[/tex]
Thus, the given answer is:
2
A. [tex]\( Mg(ClO_3)_2 + 2 HCl \rightarrow MgCl_2 + 2 HClO_3 \)[/tex]
- [tex]\( Mg(ClO_3)_2 \)[/tex]: [tex]\( Mg \)[/tex] has an oxidation state of [tex]\( +2 \)[/tex], [tex]\( Cl \)[/tex] in [tex]\( ClO_3^- \)[/tex] has an oxidation state of [tex]\( +5 \)[/tex].
- [tex]\( HCl \)[/tex]: [tex]\( H \)[/tex] is [tex]\( +1 \)[/tex], and [tex]\( Cl \)[/tex] is [tex]\( -1 \)[/tex].
- [tex]\( MgCl_2 \)[/tex]: [tex]\( Mg \)[/tex] is [tex]\( +2 \)[/tex], [tex]\( Cl \)[/tex] is [tex]\( -1 \)[/tex].
- [tex]\( HClO_3 \)[/tex]: [tex]\( H \)[/tex] is [tex]\( +1 \)[/tex], [tex]\( Cl \)[/tex] in [tex]\( ClO_3 \)[/tex] is [tex]\( +5 \)[/tex].
There are no changes in the oxidation states of any of the elements. Hence, this is not a redox reaction.
B. [tex]\( CO + H_2O \rightarrow H_2 + CO_2 \)[/tex]
- [tex]\( CO \)[/tex]: [tex]\( C \)[/tex] in [tex]\( CO \)[/tex] has an oxidation state of [tex]\( +2 \)[/tex], [tex]\( O \)[/tex] is [tex]\( -2 \)[/tex].
- [tex]\( H_2O \)[/tex]: [tex]\( H \)[/tex] is [tex]\( +1 \)[/tex], [tex]\( O \)[/tex] is [tex]\( -2 \)[/tex].
- [tex]\( H_2 \)[/tex]: [tex]\( H \)[/tex] is [tex]\( 0 \)[/tex].
- [tex]\( CO_2 \)[/tex]: [tex]\( C \)[/tex] in [tex]\( CO_2 \)[/tex] is [tex]\( +4 \)[/tex], [tex]\( O \)[/tex] is [tex]\( -2 \)[/tex].
Here, the oxidation state of [tex]\( C \)[/tex] changes from [tex]\( +2 \)[/tex] in [tex]\( CO \)[/tex] to [tex]\( +4 \)[/tex] in [tex]\( CO_2 \)[/tex], and the oxidation state of [tex]\( H \)[/tex] changes from [tex]\( +1 \)[/tex] in [tex]\( H_2O \)[/tex] to [tex]\( 0 \)[/tex] in [tex]\( H_2 \)[/tex]. Hence, this is a redox reaction.
C. [tex]\( 2 NH_4NO_3 + CuCl_2 \rightarrow 2 NH_4Cl + Cu(NO_3)_2 \)[/tex]
- [tex]\( NH_4NO_3 \)[/tex]: [tex]\( N \)[/tex] in [tex]\( NH_4^+ \)[/tex] is [tex]\( -3 \)[/tex], [tex]\( N \)[/tex] in [tex]\( NO_3^- \)[/tex] is [tex]\( +5 \)[/tex].
- [tex]\( CuCl_2 \)[/tex]: [tex]\( Cu \)[/tex] is [tex]\( +2 \)[/tex], [tex]\( Cl \)[/tex] is [tex]\( -1 \)[/tex].
- [tex]\( NH_4Cl \)[/tex]: [tex]\( N \)[/tex] in [tex]\( NH_4^+ \)[/tex] is [tex]\( -3 \)[/tex], [tex]\( Cl \)[/tex] is [tex]\( -1 \)[/tex].
- [tex]\( Cu(NO_3)_2 \)[/tex]: [tex]\( Cu \)[/tex] is [tex]\( +2 \)[/tex], [tex]\( N \)[/tex] in [tex]\( NO_3^- \)[/tex] is [tex]\( +5 \)[/tex].
There are no changes in the oxidation states of any of the elements. Hence, this is not a redox reaction.
D. [tex]\( Na_2SO_3 + FeBr_2 \rightarrow 2 NaBr + FeSO_3 \)[/tex]
- [tex]\( Na_2SO_3 \)[/tex]: [tex]\( Na \)[/tex] is [tex]\( +1 \)[/tex], [tex]\( S \)[/tex] is [tex]\( +4 \)[/tex], [tex]\( O \)[/tex] is [tex]\( -2 \)[/tex].
- [tex]\( FeBr_2 \)[/tex]: [tex]\( Fe \)[/tex] is [tex]\( +2 \)[/tex], [tex]\( Br \)[/tex] is [tex]\( -1 \)[/tex].
- [tex]\( NaBr \)[/tex]: [tex]\( Na \)[/tex] is [tex]\( +1 \)[/tex], [tex]\( Br \)[/tex] is [tex]\( -1 \)[/tex].
- [tex]\( FeSO_3 \)[/tex]: [tex]\( Fe \)[/tex] is [tex]\( +2 \)[/tex], [tex]\( S \)[/tex] is [tex]\( +4 \)[/tex], [tex]\( O \)[/tex] is [tex]\( -2 \)[/tex].
There are no changes in the oxidation states of any of the elements. Hence, this is not a redox reaction.
Based on the analysis, the chemical equation that represents a redox reaction is:
B. [tex]\( CO + H_2O \rightarrow H_2 + CO_2 \)[/tex]
Thus, the given answer is:
2
