Which formula equation shows a reversible reaction?
[tex]2 Na + F _2 \rightarrow 2 NaF[/tex]
[tex]CaCO _3 \rightarrow CaO + CO _2[/tex]
[tex]NH _4 Cl ( s ) \leftrightarrow NH _3(g)+ HCl ( g )[/tex]
[tex]2 H _2 O _2( aq ) \xrightarrow{ Br } 2 H _2 O ( l )+ O _2(g)[/tex]
Answer (2)
A reversible reaction is indicated by a double arrow ↔ .
Examine each equation to find the one with the double arrow.
The equation N H 4 Cl ( s ) ↔ N H 3 ( g ) + H Cl ( g ) has the double arrow.
Therefore, the formula equation that shows a reversible reaction is N H 4 Cl ( s ) ↔ N H 3 ( g ) + H Cl ( g ) .
Explanation
Understanding Reversible Reactions The question asks us to identify which of the given chemical equations represents a reversible reaction. A reversible reaction is characterized by the presence of a double arrow ( ↔ ) indicating that the reaction can proceed in both forward and reverse directions.
Identifying the Correct Equation Let's examine each equation:
2 N a + F 2 → 2 N a F : This equation has a single arrow, indicating an irreversible reaction.
C a C O 3 → C a O + C O 2 : This equation also has a single arrow, indicating an irreversible reaction.
N H 4 Cl ( s ) ↔ N H 3 ( g ) + H Cl ( g ) : This equation has a double arrow ( ↔ ), indicating a reversible reaction.
2 H 2 O 2 ( a q ) B r 2 H 2 O ( l ) + O 2 ( g ) : This equation has a single arrow, indicating an irreversible reaction.
Conclusion The equation with the double arrow ( ↔ ) is N H 4 Cl ( s ) ↔ N H 3 ( g ) + H Cl ( g ) . This represents a reversible reaction where ammonium chloride ( N H 4 Cl ) can decompose into ammonia ( N H 3 ) and hydrogen chloride ( H Cl ), and ammonia and hydrogen chloride can react to form ammonium chloride.
Examples
Reversible reactions are important in many chemical processes, including the production of ammonia in the Haber-Bosch process. In this process, nitrogen and hydrogen react to form ammonia, but the reaction is reversible, meaning that ammonia can also decompose back into nitrogen and hydrogen. By carefully controlling the conditions of the reaction, such as temperature and pressure, the yield of ammonia can be optimized. Another example is the dissolution of carbon dioxide in water, which is a reversible reaction that plays a crucial role in regulating the pH of oceans and other bodies of water. C O 2 ( g ) + H 2 O ( l ) ↔ H 2 C O 3 ( a q ) .
The formula equation that demonstrates a reversible reaction is N H 4 Cl ( s ) ↔ N H 3 ( g ) + H Cl ( g ) . This is indicated by the presence of a double arrow ( ↔ ). The other options present irreversible reactions, as shown by their single arrows.
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