The position of some metals in the electrochemical series in decreasing electropositive character is given as Mg > Al > Zn > Cu > Ag. What will happen if a copper spoon is used to stir a solution of aluminium nitrate?

There is no reaction

The correct answer is option 4. There is no reaction.

Let us delve into the scenario involving a copper spoon stirring a solution of aluminum nitrate, considering the electrochemical properties and reactions based on the electrochemical series.

Electrochemical Series:

The electrochemical series is a list of metals and their ions arranged in order of decreasing tendency to lose electrons (become oxidized). Metals higher in the series (like Mg, Al, and Zn) have a greater tendency to lose electrons (are more electropositive) compared to metals lower in the series (like Cu and Ag).

Given series: Mg > Al > Zn > Cu > Ag

Metals Involved:

Copper (Cu): Positioned below aluminum (Al) in the electrochemical series.

Aluminum (Al): Positioned above copper (Cu) in the electrochemical series

Reaction Potential: Aluminum (Al) has a greater tendency to undergo oxidation (lose electrons) compared to copper (Cu) because it is higher in the electrochemical series. This means in a redox reaction, aluminum can potentially oxidize copper ions (if present) back to metallic copper, while aluminum itself would reduce (gain electrons).

Aluminum Nitrate Solution: Aluminum nitrate (Al(NO₃)₃) dissociates in water to form aluminum ions (Al³⁺) and nitrate ions (NO₃⁻).

Reaction Prediction: When a copper spoon (made of metallic copper) stirs a solution of aluminum nitrate:

Copper spoon: Typically, metallic copper is not reactive with aluminum nitrate in a way that would result in the coating of aluminum on the spoon. The copper spoon would not readily react with aluminum ions in the solution.

Aluminum nitrate solution: The presence of aluminum ions (Al³⁺) in the solution does not imply they will coat the copper spoon because aluminum is not sufficiently reactive under normal conditions to displace copper from its solid state on the spoon's surface.

Analysis of Options:

(1) The spoon will get coated with aluminium: This option is incorrect because aluminum is not sufficiently reactive to displace copper from the spoon and form a coating of aluminum metal.

(2) The alloy of copper and aluminium is formed: This option is incorrect because simple stirring in a solution does not provide the conditions necessary for alloy formation between copper and aluminum.

(3) The solution becomes blue: This option is unlikely because aluminum nitrate solutions are typically colorless. A change to blue would indicate the presence of another chemical reaction, which is not described in the scenario.

(4) There is no reaction: This option is correct under normal conditions. The scenario described does not provide conditions where aluminum from the solution would react with the copper spoon to any significant degree. Aluminum is not reactive enough under these conditions to displace copper from the spoon's surface or to form a noticeable reaction product.

Based on the electrochemical series and the typical behavior of metals in solutions, the correct answer to the scenario involving a copper spoon stirring a solution of aluminum nitrate is: (4) There is no reaction.

This conclusion is drawn because aluminum is not reactive enough under normal conditions to react with the copper spoon and form a visible reaction product. Therefore, the spoon would not get coated with aluminum, and no significant reaction would occur in the solution as described.