`FeO*Cr_(2)O_(3) underset(O_(2)) overset(Na_(2)CO_(3))to A overset(H_(2)SO_(4))toB overset(KCl)toC`
The hybridisation of compound C and colour of its crystal is

Options

A. `sp^(3)` , orange red
B. `sp^(3)`, yellow
C. `sp^(2)` , orange red
D. `sp^(2)` , yellow

Answer

To solve the question regarding the hybridization of compound C and the color of its crystal, we will follow these steps:

### Step 1: Identify the Reaction Products
We start with the reaction of FeO and Cr₂O₃ with Na₂CO₃ and O₂. The balanced reaction gives us:
\[ \text{FeO} \cdot \text{Cr}_2\text{O}_3 + \text{Na}_2\text{CO}_3 + \text{O}_2 \rightarrow \text{Na}_2\text{CrO}_4 + \text{Fe}_2\text{O}_3 + \text{CO}_2 \]

Here, the product A is identified as Na₂CrO₄.

### Step 2: Reaction with H₂SO₄
Next, we react compound A (Na₂CrO₄) with H₂SO₄:
\[ \text{Na}_2\text{CrO}_4 + \text{H}_2\text{SO}_4 \rightarrow \text{CrO}_3 + \text{Na}_2\text{SO}_4 + \text{H}_2\text{O} \]

From this reaction, we identify compound B as CrO₃.

### Step 3: Reaction with KCl
Now, we react compound B (CrO₃) with KCl:
\[ \text{CrO}_3 + \text{KCl} \rightarrow \text{KCrO}_3\text{Cl} \]

This gives us compound C, which is KCrO₃Cl.

### Step 4: Determine the Hybridization of Compound C
To find the hybridization of compound C (KCrO₃Cl), we need to calculate the steric number of the central atom, which is chromium (Cr).

1. **Count the Lone Pairs on Chromium:**
- In KCrO₃Cl, chromium is bonded to three oxygen atoms and one chlorine atom. There are no lone pairs on chromium.
- Lone pairs = 0

2. **Count the Atoms Bonded to Chromium:**
- Chromium is bonded to 4 atoms (3 O and 1 Cl).
- Bonded atoms = 4

3. **Calculate the Steric Number:**
\[ \text{Steric Number} = \text{Lone Pairs} + \text{Bonded Atoms} = 0 + 4 = 4 \]

4. **Determine the Hybridization:**
- A steric number of 4 corresponds to an sp³ hybridization.

### Step 5: Identify the Color of Compound C
The color of KCrO₃Cl is typically described as orange-red.

### Final Answer
- **Hybridization of Compound C:** sp³
- **Color of its Crystal:** Orange-red