Assertion : Aqueous solution of the compound `CoCl_(3) * 4NH_(3)` when treated with excess of `AgNO_3` , 1 mole of AgCl is precipitated .
Reason : The compound `CoCl_(3) * 4NH_(3)` has six primary valencies and one secondary valency .

Options

A. If both Assertion and reason are true and reason is the correct explanation of assertion
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but reason is false
D. if both assertion and reason are false

Explanation

To solve the given question, we need to analyze both the assertion and the reason provided.

### Step 1: Analyze the Assertion
The assertion states that when an aqueous solution of the compound \( CoCl_3 \cdot 4NH_3 \) is treated with excess \( AgNO_3 \), 1 mole of \( AgCl \) is precipitated.

**Solution:**
1. The compound \( CoCl_3 \cdot 4NH_3 \) can dissociate in solution to give:
\[ CoCl_3 \cdot 4NH_3 \rightarrow Co(NH_3)_4^{3+} + 3Cl^- \]
2. The chloride ions \( Cl^- \) will react with \( Ag^+ \) ions from \( AgNO_3 \) to form \( AgCl \) precipitate:
\[ Ag^+ + Cl^- \rightarrow AgCl(s) \]
3. Since there are 3 moles of \( Cl^- \) produced from the dissociation of \( CoCl_3 \cdot 4NH_3 \), it can indeed precipitate 1 mole of \( AgCl \) for each mole of \( Cl^- \) present.

Thus, the assertion is **correct**.

### Step 2: Analyze the Reason
The reason states that the compound \( CoCl_3 \cdot 4NH_3 \) has six primary valencies and one secondary valency.

**Solution:**
1. According to Werner's theory, primary valencies are associated with the charge of the metal ion, while secondary valencies refer to the coordination number (number of ligands attached).
2. In \( CoCl_3 \cdot 4NH_3 \):
- Cobalt (Co) typically has a +3 oxidation state in this compound.
- The three \( Cl^- \) ions can be considered to satisfy the primary valency.
- The four \( NH_3 \) molecules coordinate with cobalt, satisfying the secondary valency.
3. Therefore, cobalt has 3 primary valencies (from the 3 \( Cl^- \) ions) and 6 secondary valencies (from the 4 \( NH_3 \) ligands and the 2 \( Cl^- \) that can also act as ligands).

Thus, the reason is **incorrect** as it states there are 6 primary valencies and 1 secondary valency.

### Conclusion
- The assertion is **true**.
- The reason is **false**.

The correct answer is that the assertion is true but the reason is false.

### Final Answer
The correct option is C: Assertion is true, Reason is false.

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