An experimenter attempts to carry out a single replacement reaction between solid copper and a solution of hydrogen fluoride.
Which is more reactive - copper or hydrogen?
Which of the following equations correctly predicts the products of the reaction?
i. $2 Cu _{( s )}+2 HF _{( aq )} \rightarrow F _{2(g)}+2 HCu _{( aq )}$
ii. $Cu _{( s )}+ HF _{( aq )} \rightarrow CuHF _{( s )}$
iii. $2 Cu _{( s )}+2 HF _{( aq )} \rightarrow H _{2(g)}+2 CuF _{( aq )}$
iv. $Cu _{( s )}+ HF _{( aq )} \rightarrow$ no reaction
Answer (2)
Hydrogen is more reactive than copper.
Copper cannot displace hydrogen from hydrogen fluoride because it is less reactive.
Therefore, no reaction occurs.
The correct equation is: C u ( s ) + H F ( a q ) → no reaction.
Explanation
Problem Analysis We are given a single replacement reaction between solid copper (Cu) and a solution of hydrogen fluoride (HF). We need to determine which is more reactive, copper or hydrogen, and then identify the correct chemical equation for the reaction.
Reactivity Determination To determine the relative reactivity, we need to consider the activity series of metals. In the activity series, a more reactive metal will displace a less reactive metal (or hydrogen) from its compounds. Copper is below hydrogen in the activity series, which means hydrogen is more reactive than copper.
Reaction Prediction Since copper is less reactive than hydrogen, it cannot displace hydrogen from hydrogen fluoride (HF). Therefore, no reaction will occur.
Equation Selection Now, let's examine the given equations to find the one that correctly represents the predicted reaction (or lack thereof). The correct equation should indicate 'no reaction'.
Final Answer The correct equation is: C u ( s ) + H F ( a q ) i g h t ha r p oo n u p no reaction
Examples
Single replacement reactions are important in various industrial processes, such as metal refining and the production of new materials. For example, if you want to extract a pure metal from its ore, you might use a more reactive metal to displace the desired metal from its compound. Understanding the activity series and predicting whether a reaction will occur is crucial in these applications. Also, consider electroplating, where a metal is deposited onto a surface using electrochemical reactions; the principles of reactivity and displacement are fundamental to this process.
Hydrogen is more reactive than copper, meaning no reaction occurs between solid copper and hydrogen fluoride. The correct equation representing this situation is: C u ( s ) + H F ( a q ) → no reaction.
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