Question

To displace \(\mathrm{Br}_{2}\) from an aqueous solution of \(\mathrm{Br}^{-}\) add \((\mathrm{a}) \mathrm{I}_{2}(\mathrm{aq}) ;\) (b) \(\mathrm{Cl}_{2}(\mathrm{aq}) ;\) (c) \(\mathrm{H}_{2}(\mathrm{g}) ;\) (d) \(\mathrm{Cl}^{-}(\mathrm{aq})\) (e) \(\mathrm{I}_{3}^{-}(\mathrm{aq})\).

Short answer

The Chlorine (\(Cl_{2}\)) can displace the Bromine (\(Br_{2}\)) from its aqueous solution, while other given chemicals (Iodine, Hydrogen, Chloride ion, and Triiodide ion) cannot.

Step-by-step solution

Analyze Each Chemical

This involves looking at each chemical in the list and determining its position in the reactivity series of halogens.

Predict the Possibility of each Displacement

If a halogen in the list is more reactive than the Bromine in the aqueous solution (i.e., it is higher in the reactivity series), it can displace the Bromine. Otherwise, it cannot displace the Bromine.

Summarize Results

(a) Iodine (\(I_2\)): Iodine is less reactive than Bromine; no displacement will occur. (b) Chlorine (\(Cl_2\)): Chlorine is more reactive than Bromine and will displace the Bromine to form \(Br_{2}\). (c) Hydrogen (\(H_2\)): Hydrogen does not belong to the halogen group and doesn't displace Bromine from its aqueous solution. (d) Chloride ion (\(Cl^{-}\)): even though \(Cl_2\) is more reactive, ions generally do not participate in such displacement reactions. (e) Triiodide ion (\(I_{3}^{-}\)): Iodine is less reactive than Bromine, so there will be no displacement.

Key concepts

Displacement Reactions

Displacement reactions are fascinating. They occur when a more reactive element replaces a less reactive element in a compound. In halogens, this happens when a more active halogen displaces a less active one from its compound. For instance, if we have bromine in a solution, chlorine, which is more reactive, would displace it. However, iodine, being less reactive, can't knock bromine out of its place. The concept revolves around trying to achieve stability or a more favorable energy state. When talking about halogen reactions, it's essential to remember that only halogens more reactive than the one in the compound can displace it. If a less reactive element tries, nothing will happen.

• More reactive elements displace less reactive ones.
• The element being displaced gets released from the compound.
• Displacement is also a fabulous way to look at the reactivity series in action.

Reactivity Series

The reactivity series is a powerful tool in chemistry that ranks elements by their chemical activity. For halogens, the series from most to least reactive is: fluorine, chlorine, bromine, and iodine. This order tells us a lot about behavior in reactions. For example, chlorine can displace both bromine and iodine, but not the other way around. Understanding the series helps predict the outcomes of chemical reactions, particularly displacement reactions. When examining a reactivity series, it's crucial to know the position of each element. Only those above another in this series can push them out of compounds like halide solutions.

• The higher up an element is on the series, the more reactive it is.
• Position in the series determines its ability to displace others.
• Follows a specific order: fluorine, chlorine, bromine, iodine.

Chemical Reactivity

Chemical reactivity denotes how easily an element will partake in a chemical reaction. This "eagerness" or readiness depends largely on the element's position in the reactivity series. It encapsulates the concept that certain elements can more efficiently lure others into reactions. For halogens, chemical reactivity decreases as you move down the group in the periodic table. So, from fluorine to iodine, there's a diminishing tendency to react. This trend is crucial for predicting displacement. When you know the relative reactivities, forecasting the reaction becomes straightforward.

• Chemical reactivity varies across the periodic table.
• An element's ability to engage in reactions defines its reactivity.
• For halogens, reactivity declines from fluorine to iodine.