The oxidation and coordination numbers of cobalt in the compound [Co(NH₃)₅Cl]Cl₂ are, respectively: A) 2 and 6. B) 2 and 8. C) 3 and 6. D) 3 and 8. E) none of the above

Question

Quizplus · Accepted Answer

The coordination number of cobalt can be determined by counting the number of ligands (ions or molecules) directly bonded to it. In this compound, cobalt is coordinated to one chloride ion and one polydentate ligand, [Co(NH₃)₅Cl]. To determine the oxidation number of cobalt, we start by assigning oxidation numbers to the other atoms in the compound. Chlorine typically has an oxidation number of -1, and the sum of oxidation numbers in a neutral compound must be zero. Thus, the oxidation number of cobalt can be obtained by solving the equation: x + (-1) + (1) + 2(-1) = 0 Where x is the oxidation number of cobalt. Solving for x gives x = +3. Therefore, the oxidation and coordination numbers of cobalt in the compound are 3 and 6, respectively. Therefore, the best choice is C.

The Oxidation and Coordination Numbers of Cobalt in the Compound