Statement 1: Bromine has a higher boiling point than chlorine. Statement 2: Bromine has stronger dispersion forces than chlorine. (A) Both statement 1 and statement 2 are correct and statement 2 is the correct explanation of statement 1. (B) Both statement 1 and statement 2 are correct and statement 2 is not the correct explanation of statement 1. (C) Statement 1 is correct but statement 2 is not correct. (D) Statement 1 is not correct but statement 2 is correct. (E) Both statement 1 and statement 2 are not correct.
Hint: All the halogens exist as diatomic molecules in the elemental state. The size of the halogens goes on increasing down a group. With this increase in size, the van der Waals forces of attraction also increase down a group.
Complete step by step answer: Bromine lies below chlorine in the halogen group. So, bromine has more number of shells than chlorine. As a result, bromine is larger in size and has a larger atomic radius than that of chlorine. Thus, bromine has higher molar mass than chlorine. This difference in size and molar mass relates to the boiling point of the molecule. With the increase in size of a molecule, the strength of the forces between the molecules or in other words, the intermolecular forces called van der Waals forces increases. Since bromine has larger size than chlorine, it will have stronger intermolecular forces and so more heat energy is required to break the strong bonds. Thus, bromine has a higher boiling point than chlorine. So, the statement 1 is correct. Dispersion forces or London dispersion forces are temporary forces that result when the electrons in two nearby atoms occupy positions that make the atoms temporary dipoles. These are present between any molecules, whether polar or non-polar when they are almost touching. Dispersion forces are displayed more strongly by larger and heavier atoms than smaller and light atoms. This is because in a larger atom or molecule, the outermost shell electrons lie more far away from the nucleus than in a smaller atom or molecule. So, they are loosly held and hence can easily form dipoles. Thus, since bromine is larger and heavier than chlorine, bromine will display higher dispersion forces than chlorine. Hence, statement 2 is also correct. Thus, larger the atom or molecule, stronger will be the dispersion force or van der Waals forces of attraction, which in turn will result in a higher boiling point.
Hence, the correct option is A.
Note: Some other differences between bromine and chlorine are also available. Bromine is less reactive than chlorine. Bromine occurs in nature in the form of two stable isotopes but chlorine only occurs in the form of chemical compounds or remains dissociated in the form of ions. Bromine can exhibit an oxidation state of -1 and any odd positive state of +1, +3, +5 and +7. On the other hand, chlorine exhibits all oxidation states from -1 to +7, except +2.