Which of the following statements is/are correct, when a mixture of `NaCl` and `K_2Cr_2O_7` is gently warmed with concentrated `H_2SO_4`?

Options

A. `CrO_2Cl_2`
B. `CrCl_3`
C. `Cr_2(SO_4)_3`
D. `Na_2CrO_4`

Answer

To solve the question regarding the reaction of a mixture of NaCl and K2Cr2O7 when gently warmed with concentrated H2SO4, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**: The reactants in this scenario are sodium chloride (NaCl) and potassium dichromate (K2Cr2O7) mixed together.

2. **Understand the Reaction with Concentrated H2SO4**: When NaCl is treated with concentrated sulfuric acid (H2SO4), it can lead to the formation of hydrogen chloride (HCl) gas. The potassium dichromate (K2Cr2O7) can also react with H2SO4.

3. **Write the Reaction**: The overall reaction can be represented as:
\[ 2 \text{K}_2\text{Cr}_2\text{O}_7 + 6 \text{NaCl} + 6 \text{H}_2\text{SO}_4 \rightarrow 2 \text{KHSO}_4 + 4 \text{NaHSO}_4 + 2 \text{CrO}_2\text{Cl}_2 + 3 \text{H}_2\text{O} \]
In this reaction, potassium bisulfate (KHSO4), sodium bisulfate (NaHSO4), dichlorine oxide (CrO2Cl2), and water (H2O) are produced.

4. **Color Change Observation**: The product CrO2Cl2 is known to have a deep orange-red color. This indicates a significant change in color due to the formation of this compound.

5. **Conclusion**: Based on the reaction, we can conclude that the formation of CrO2Cl2 and the resulting color change are key observations. Therefore, the statement regarding the formation of orange-red color due to CrO2Cl2 is correct.

### Final Answer:
The correct statement is that a deep orange-red color is formed due to the production of CrO2Cl2 when NaCl and K2Cr2O7 are warmed with concentrated H2SO4.