A metal complex having composition `Cr(NH_(3))_(4)CI_(2)` Br has been isolated in two forms `A` and `B` The `A` reacts with `AgNO_(3)` to give a white precipitate readily soluble in dilute queous ammonia, whereas `B` gives a pale-yellow precipitate soluble in concentrated ammonia Write the formula of `A` and `B` and state the hybridisation of chromium in each. Calculate their magnetic moment (spin only value) .

Explanation

To solve the problem, we need to identify the two forms of the chromium complex, determine their formulas, state the hybridization of chromium in each, and calculate their magnetic moments.

### Step 1: Identify the Complexes A and B

1. **Complex A**:
- It reacts with AgNO₃ to give a white precipitate that is soluble in dilute aqueous ammonia.
- This indicates that the chloride ion (Cl⁻) is outside the coordination sphere.
- Therefore, the formula for complex A is:
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