The total number of ions produced by dichloridobis(ethane-1,2-diamine)cobalt(III) chloride in aqueous solution is:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 2
The IUPAC name tells us what is inside and what is outside the coordination sphere. The ligands named before the metal are inside the square bracket; the anion named last is the counter ion outside it.
dichlorido: two \( \ce{Cl^{-}} \) ligands inside the sphere
bis(ethane-1,2-diamine): two neutral en ligands inside the sphere
cobalt(III): central metal in the +3 state
chloride: counter ion outside the sphere
Charge on the complex ion:
\( \displaystyle (+3)+2(0)+2(-1)=+1 \)
So one \( \ce{Cl^{-}} \) balances it and the formula is \( \ce{[Co(en)2Cl2]Cl} \). In water it ionises as:
\( \displaystyle \ce{[Co(en)2Cl2]Cl -> [Co(en)2Cl2]^+ + Cl^-} \)
So the total number of ions is 2.