The absorption of [Co(NH3)6]2+ is:*2 pointsStronger than that of [Co(NH3)5Cl]2+Stronger than that of [MnCl4]2-Weaker than that of [MnCl4]2- but stronger than that of [Co(NH3)5Cl]2+Weaker than those of [MnCl4]2- & [Co(NH3)5Cl]2+ both

The absorption of a compound in solution is determined by its molar absorptivity, which is a measure of how strongly the compound absorbs light at a given wavelength. This property is influenced by the structure of the compound, including the type and arrangement of its atoms, and the nature of its chemical bonds.

1. Comparing [Co(NH3)6]2+ and [Co(NH3)5Cl]2+: Both of these compounds contain cobalt, but [Co(NH3)6]2+ has six ammonia ligands, while [Co(NH3)5Cl]2+ has five ammonia ligands and one chloride ligand. The presence of the chloride ligand in [Co(NH3)5Cl]2+ may cause it to absorb light more strongly than [Co(NH3)6]2+, because chloride is a stronger field ligand than ammonia. Therefore, the absorption of [Co(NH3)6]2+ is likely weaker than that of [Co(NH3)5Cl]2+.

2. Comparing [Co(NH3)6]2+ and [MnCl4]2-: Both of these compounds contain transition metals, but they have different ligands and different metal ions. Manganese in [MnCl4]2- is in a lower oxidation state than cobalt in [Co(NH3)6]2+, and chloride is a stronger field ligand than ammonia. Therefore, the absorption of [Co(NH3)6]2+ is likely weaker than that of [MnCl4]2-.

3. Comparing [Co(NH3)6]2+ with both [MnCl4]2- and [Co(NH3)5Cl]2+: Based on the above comparisons, the absorption of [Co(NH3)6]2+ is likely weaker than those of both [MnCl4]2- and [Co(NH3)5Cl]2+.

So, the correct answer is: "Weaker than those of [MnCl4]2- & [Co(NH3)5Cl]2+ both".

Please note that this is a simplified explanation and the actual absorption of these compounds in solution can be influenced by many other factors, including the concentration of the solution, the temperature, and the presence of other species in the solution.