Question

The IUPAC name of the given compound \([Co(NH_3)_5Cl]Cl_2\) is

• A. pentaamino cobalt chloride chlorate
• B. cobalt pentaamine chloro chloride
• C. pentaamine chloro cobalt(III) chloride
• D. pentaamino cobalt(III) chlorate

Hint:

In coordination compounds, name ligands alphabetically, then metal with oxidation state, then counter ion.

Answer 1

The Correct Option is C

Step 1: Identify complex ion and counter ions.
\[ [Co(NH_3)_5Cl]Cl_2 \]
Complex ion: \([Co(NH_3)_5Cl]^{2+}\)
Counter ions: \(2Cl^-\)
Step 2: Find oxidation state of cobalt.
Let oxidation state of Co be \(x\).
Ligands:
NH\(_3\) is neutral, Cl is \(-1\).
Charge on complex is \(+2\).
\[ x + 0\times 5 + (-1) = +2 \Rightarrow x = +3 \]
Step 3: Name ligands in alphabetical order.
NH\(_3\) = ammine (5) \(\Rightarrow\) pentaammine
Cl = chloro (1)
Alphabetically: ammine comes before chloro, so order is pentaammine chloro.
Step 4: Name the metal with oxidation state.
Cobalt(III).
Step 5: Name counter ion.
Chloride.
Step 6: Final name.
\[ \text{pentaamminechloro cobalt(III) chloride} \]
Final Answer:
\[ \boxed{\text{pentaamine chloro cobalt(III) chloride}} \]