Answer :
Let's classify each of the given chemical reactions step by step:
1. Reaction 1: [tex]\( Mg (s) + FeCl_2 (aq) \rightarrow MgCl_2 (aq) + Fe (s) \)[/tex]
- In this reaction, magnesium ([tex]\(Mg\)[/tex]) is combining with iron(II) chloride ([tex]\(FeCl_2\)[/tex]).
- Magnesium replaces iron in the compound, resulting in magnesium chloride ([tex]\(MgCl_2\)[/tex]) and elemental iron ([tex]\(Fe\)[/tex]).
- This type of reaction where one element replaces another element in a compound is called a single replacement (or displacement) reaction.
2. Reaction 2: [tex]\( 2 KNO_3 (s) \rightarrow 2 KNO_2 (s) + O_2 (g) \)[/tex]
- This reaction involves the breakdown of potassium nitrate ([tex]\(KNO_3\)[/tex]) into potassium nitrite ([tex]\(KNO_2\)[/tex]) and oxygen gas ([tex]\(O_2\)[/tex]).
- When a single compound breaks down into two or more simpler products, the reaction is known as a decomposition reaction.
3. Reaction 3: [tex]\( FeCl_2 (aq) + Na_2S (aq) \rightarrow 2 NaCl_2 (aq) + FeS (s) \)[/tex]
- In this reaction, iron(II) chloride ([tex]\(FeCl_2\)[/tex]) reacts with sodium sulfide ([tex]\(Na_2S\)[/tex]) to produce sodium chloride ([tex]\(NaCl_2\)[/tex]) and iron(II) sulfide ([tex]\(FeS\)[/tex]).
- This reaction involves the exchange of ions between two compounds which results in the formation of two new compounds.
- Such reactions, where two compounds swap components to form two different compounds, are classified as double replacement (or double displacement) reactions.
4. Reaction 4: [tex]\( Mg (s) + F_2 (g) \rightarrow MgF_2 (s) \)[/tex]
- In this reaction, magnesium ([tex]\(Mg\)[/tex]) combines directly with fluorine ([tex]\(F_2\)[/tex]) to form magnesium fluoride ([tex]\(MgF_2\)[/tex]).
- When two or more simple substances combine to form a more complex substance, the reaction is known as a synthesis (or combination) reaction.
To summarize:
[tex]\[ \begin{array}{|c|c|} \hline \text{Reaction} & \text{Classification} \\ \hline Mg (s) + FeCl_2 (aq) \rightarrow MgCl_2 (aq) + Fe (s) & \text{single replacement} \\ \hline 2 KNO_3 (s) \rightarrow 2 KNO_2 (s) + O_2 (g) & \text{decomposition} \\ \hline FeCl_2 (aq) + Na_2S (aq) \rightarrow 2 NaCl_2 (aq) + FeS (s) & \text{double replacement} \\ \hline Mg (s) + F_2 (g) \rightarrow MgF_2 (s) & \text{synthesis} \\ \hline \end{array} \][/tex]
1. Reaction 1: [tex]\( Mg (s) + FeCl_2 (aq) \rightarrow MgCl_2 (aq) + Fe (s) \)[/tex]
- In this reaction, magnesium ([tex]\(Mg\)[/tex]) is combining with iron(II) chloride ([tex]\(FeCl_2\)[/tex]).
- Magnesium replaces iron in the compound, resulting in magnesium chloride ([tex]\(MgCl_2\)[/tex]) and elemental iron ([tex]\(Fe\)[/tex]).
- This type of reaction where one element replaces another element in a compound is called a single replacement (or displacement) reaction.
2. Reaction 2: [tex]\( 2 KNO_3 (s) \rightarrow 2 KNO_2 (s) + O_2 (g) \)[/tex]
- This reaction involves the breakdown of potassium nitrate ([tex]\(KNO_3\)[/tex]) into potassium nitrite ([tex]\(KNO_2\)[/tex]) and oxygen gas ([tex]\(O_2\)[/tex]).
- When a single compound breaks down into two or more simpler products, the reaction is known as a decomposition reaction.
3. Reaction 3: [tex]\( FeCl_2 (aq) + Na_2S (aq) \rightarrow 2 NaCl_2 (aq) + FeS (s) \)[/tex]
- In this reaction, iron(II) chloride ([tex]\(FeCl_2\)[/tex]) reacts with sodium sulfide ([tex]\(Na_2S\)[/tex]) to produce sodium chloride ([tex]\(NaCl_2\)[/tex]) and iron(II) sulfide ([tex]\(FeS\)[/tex]).
- This reaction involves the exchange of ions between two compounds which results in the formation of two new compounds.
- Such reactions, where two compounds swap components to form two different compounds, are classified as double replacement (or double displacement) reactions.
4. Reaction 4: [tex]\( Mg (s) + F_2 (g) \rightarrow MgF_2 (s) \)[/tex]
- In this reaction, magnesium ([tex]\(Mg\)[/tex]) combines directly with fluorine ([tex]\(F_2\)[/tex]) to form magnesium fluoride ([tex]\(MgF_2\)[/tex]).
- When two or more simple substances combine to form a more complex substance, the reaction is known as a synthesis (or combination) reaction.
To summarize:
[tex]\[ \begin{array}{|c|c|} \hline \text{Reaction} & \text{Classification} \\ \hline Mg (s) + FeCl_2 (aq) \rightarrow MgCl_2 (aq) + Fe (s) & \text{single replacement} \\ \hline 2 KNO_3 (s) \rightarrow 2 KNO_2 (s) + O_2 (g) & \text{decomposition} \\ \hline FeCl_2 (aq) + Na_2S (aq) \rightarrow 2 NaCl_2 (aq) + FeS (s) & \text{double replacement} \\ \hline Mg (s) + F_2 (g) \rightarrow MgF_2 (s) & \text{synthesis} \\ \hline \end{array} \][/tex]