Which of the following complexes possesses a central metal atom with a primary valency of ? — Coordination Compounds Chemistry Question

💡 Solution & Explanation

Primary valency corresponds to the oxidation state of the central metal. Let's calculate the oxidation state ($x$) for each option: (A) $[Co(NH_3)_5Cl]Cl \Rightarrow x + 5(0) + (-1) = +1 \Rightarrow x = +2$ (B) $[Co(NH_3)_4Cl_2]Cl \Rightarrow x + 4(0) + 2(-1) = +1 \Rightarrow x = +3$ (C) $[Co(NH_3)_3Cl_3] \Rightarrow x + 3(0) + 3(-1) = 0 \Rightarrow x = +3$ (D) $[Co(H_2O)_4Cl_2]Cl \Rightarrow x + 4(0) + 2(-1) = +1 \Rightarrow x = +3$ Only option A has a primary valency of $2$.