Assertion : Solid potassium dichromate gives greenish yellow vapour with concentrated `H_(2) SO_(4)` and solid ammonium chloride.
Reason : The reaction of ammonium chloride with solide `K_(2) Cr_(2) O_(7)` and concentrated `H_(2) SO_(4)` produces chromyl chloride.

Options

A. Statement-1 is true , Statement-2 is true and Statement-2 is correct explanation for Statement-1
B. Statement-1 is true, Statement-2 is True and Statement-2 is Not correct explanation for statement-1
C. Statement-1 is true, Statement-2 is False
D. Statement-1 is False, Statement-2 is True

Answer

To solve the question regarding the assertion and reason about potassium dichromate, we will break it down step by step.

### Step 1: Analyze the Assertion
The assertion states that solid potassium dichromate (K₂Cr₂O₇) gives greenish-yellow vapors when reacted with concentrated sulfuric acid (H₂SO₄) and solid ammonium chloride (NH₄Cl).

**Hint:** Consider the physical properties and color of the products formed in the reaction.

### Step 2: Analyze the Reason
The reason states that the reaction of ammonium chloride with solid potassium dichromate and concentrated sulfuric acid produces chromyl chloride (CrO₂Cl₂).

**Hint:** Recall the chemical reaction that occurs when these substances are mixed and identify the products formed.

### Step 3: Write the Chemical Reaction
When potassium dichromate reacts with ammonium chloride and concentrated sulfuric acid, the following reaction occurs:

\[ K_2Cr_2O_7 + 4 NH_4Cl + 3 H_2SO_4 \rightarrow 2 CrO_2Cl_2 + 2 (NH_4)_2SO_4 + 3 H_2O \]

**Hint:** Ensure you understand the stoichiometry and the balancing of the chemical equation.

### Step 4: Identify the Color of the Product
The product chromyl chloride (CrO₂Cl₂) is known to be a deep red or reddish-orange color, not greenish-yellow.

**Hint:** Compare the expected color of the assertion with the actual color of the product formed.

### Step 5: Conclusion
- The assertion is **false** because it incorrectly describes the color of the vapors produced.
- The reason is **true** as it correctly states that the reaction produces chromyl chloride.

### Final Answer
The assertion is false, and the reason is true. Therefore, the correct option is that the assertion is incorrect while the reason is correct.