Question

Complete and balance the following equations. If no reaction occurs, write \(\mathrm{NR}\). (a) \(\mathrm{Cl}_{2}(g)+\mathrm{Br}^{-}(a q) \longrightarrow\) (b) \(\mathrm{I}_{2}(s)+\mathrm{Cl}^{-}(a q) \longrightarrow\) (c) \(\mathrm{I}_{2}(s)+\mathrm{Br}^{-}(a q) \longrightarrow\) (d) \(\mathrm{Br}_{2}(l)+\mathrm{Cl}^{-}(a q) \longrightarrow\)

Short answer

Question: Arrange the given halogens in order of their reactivity and explain their tendency of displacement in the chemical reactions. Answer: The reactivity of halogens decreases as we move down the group, with Fluorine being the most reactive and Iodine being the least reactive. The order of reactivity is: F₂ > Cl₂ > Br₂ > I₂. Halogens with higher reactivity can displace halogens with lower reactivity from their salts. This displacement reaction is a redox reaction where the more reactive halogen is reduced while the less reactive halogen is oxidized.

Step-by-step solution

(a) Identify the products and balance the equation

First, we need to determine if a reaction occurs. Since Cl₂ has a higher reactivity than Br⁻, a displacement reaction occurs; Cl₂ replaces Br⁻. Thus, the products will be Cl⁻ and Br₂. Now, let's write down the complete equation: \(\mathrm{Cl}_{2}(g)+2 \mathrm{Br}^{-}(a q) \longrightarrow 2 \mathrm{Cl}^{-}(a q) + \mathrm{Br}_{2}(l)\)

(b) Identify the products and balance the equation

Let's see if a reaction occurs in this case. Since I₂ has a lower reactivity than Cl⁻, no displacement reaction will take place in this case. So, we simply write "NR" as the answer: \(\mathrm{NR}\)

(c) Identify the products and balance the equation

For this reaction, we need to check if I₂ can displace Br⁻. Once again, I₂ has a lower reactivity than Br⁻; hence, no displacement reaction will occur. So, the answer is: \(\mathrm{NR}\)

(d) Identify the products and balance the equation

In this case, we compare the reactivities of Br₂ and Cl⁻. Br₂ has a higher reactivity than Cl⁻; therefore, a displacement reaction occurs. Br₂ replaces Cl⁻, producing Br⁻ and Cl₂. Now, let's write the complete and balanced equation: \(\mathrm{Br}_{2}(l)+2 \mathrm{Cl}^{-}(a q) \longrightarrow 2 \mathrm{Br}^{-}(a q) + \mathrm{Cl}_{2}(g)\)