Question

The later halogens form pentafluorid es: CIF5, BrF5, and IF5. At 0°C, one of these is a solid, one a liquid, and one a gas.

Specify which is which, and explain your reasoning.

Answer 1

At 0°C, ClF5 is likely a gas due to weaker molecular interactions than BrF5 and IF5. BrF5 is a liquid as it has stronger molecular forces than ClF5 but not as strong as IF5. IF5 is a solid, having the strongest molecular interactions of the three.

Step-by-step explanation:

The halogens form pentafluorides, and the states of matter for ClF5, BrF5, and IF5 at 0°C can be determined by looking at the trends of their elements' physical states. Generally, as the molar mass and the size of the atoms increase from fluorine to iodine, the forces of attraction between the molecules become stronger, leading to a higher boiling point and a more solid state. However, in the case of pentafluorides, we'll need to apply this reasoning to these specific compounds.

Chlorine is smaller and lighter than bromine and iodine, which suggests that the molecular interactions in ClF5 will be weaker than in BrF5 and IF5. Therefore, we could theorize that ClF5 would likely be a gas at 0°C. Bromine lies between chlorine and iodine in terms of atomic size and molecular weight, so BrF5 might be expected to be a liquid due to having stronger molecular forces than ClF5 but not as strong as IF5. Since iodine has the largest atoms and the highest molecular weight of the three, one would predict IF5 to have the strongest molecular interactions and therefore be a solid at 0°C.