Why does no reaction occur when iodine is added to sodium bromide solution?

The correct answer is that iodine is less reactive than bromine. In the context of halogen chemistry, reactivity is a crucial concept. Halogens can displace each other in chemical reactions based on their reactivity series. Bromine is more reactive than iodine, meaning that when sodium bromide, which contains the bromide ion (Br⁻), is in solution, iodine (I₂) cannot displace the bromide ions.

Since iodine cannot effectively displace the bromine from the sodium bromide solution, no reaction occurs when iodine is added. This illustrates the principle that a less reactive halogen cannot replace a more reactive halogen in a compound.

While other options mention reactivity of iodine with chlorine or sodium, they do not directly relate to the specific scenario of iodine's interaction with bromine, emphasizing the importance of understanding the relative reactivities of the halogens involved in this reaction.