The aqueous solution of one of the following will turn China rose indicator from light pink to green. This solution is of :

Options

A. vinegar
B. baking soda
C. lemon juice
D. carbonic acid

Answer

To determine which aqueous solution will turn China rose indicator from light pink to green, we need to analyze the options provided and understand the behavior of the China rose indicator in different pH environments.

### Step-by-Step Solution:

1. **Understanding China Rose Indicator**:
- China rose indicator is a natural pH indicator that changes color based on the acidity or basicity of a solution.
- In acidic solutions, it appears pink, and in basic solutions, it turns green.

2. **Identifying the Required Solution**:
- Since we want the indicator to change from light pink to green, we need a basic solution.

3. **Analyzing the Options**:
- We will evaluate each option to see if it produces a basic solution when dissolved in water.

4. **Option 1: Sodium Carbonate (Na2CO3)**:
- Sodium carbonate is a salt derived from a weak acid (carbonic acid) and a strong base (sodium hydroxide).
- When dissolved in water, it undergoes hydrolysis to produce a basic solution:
\[ \text{Na}_2\text{CO}_3 + \text{H}_2\text{O} \rightarrow 2\text{Na}^+ + \text{HCO}_3^- + \text{OH}^- \]
- This indicates that sodium carbonate will produce hydroxide ions (OH⁻), making the solution basic.

5. **Option 2: Sodium Chloride (NaCl)**:
- Sodium chloride is a salt from a strong acid (hydrochloric acid) and a strong base (sodium hydroxide).
- When dissolved in water, it remains neutral:
\[ \text{NaCl} \rightarrow \text{Na}^+ + \text{Cl}^- \]
- This does not change the pH significantly, so it will not turn the indicator green.

6. **Option 3: Sodium Sulfate (Na2SO4)**:
- Sodium sulfate is also a salt from a strong acid (sulfuric acid) and a strong base (sodium hydroxide).
- Similar to sodium chloride, it remains neutral when dissolved in water:
\[ \text{Na}_2\text{SO}_4 \rightarrow 2\text{Na}^+ + \text{SO}_4^{2-} \]
- It will not produce a basic solution.

7. **Option 4: Ammonium Chloride (NH4Cl)**:
- Ammonium chloride is a salt from a weak base (ammonia) and a strong acid (hydrochloric acid).
- When dissolved in water, it produces an acidic solution:
\[ \text{NH}_4\text{Cl} + \text{H}_2\text{O} \rightarrow \text{NH}_4^+ + \text{Cl}^- + \text{H}_2\text{O} \]
- This will not turn the indicator green, as it is acidic.

8. **Conclusion**:
- The only option that produces a basic solution is **Sodium Carbonate (Na2CO3)**. Therefore, this is the correct answer.

### Final Answer:
The solution of sodium carbonate (Na2CO3) will turn the China rose indicator from light pink to green.