Which one of the following solutions will not turn blue litmus red?
Lemon juice
Acetic acid
Sodium hydroxide
HCl

Options

A. Lemon juice
B. Acetic acid
C. Sodium hydroxide
D. HCl

Answer

To determine which solution will not turn blue litmus red, we need to analyze the properties of each option given:

1. **Lemon Juice**:
- Lemon juice contains citric acid.
- Since it is an acid, it will turn blue litmus paper red.

2. **Acetic Acid**:
- Acetic acid (vinegar) is also an acid.
- Therefore, it will also turn blue litmus paper red.

3. **Sodium Hydroxide (NaOH)**:
- Sodium hydroxide is a strong base.
- Bases do not turn blue litmus red; instead, they turn red litmus blue.

4. **Hydrochloric Acid (HCl)**:
- Hydrochloric acid is a strong acid.
- It will turn blue litmus paper red.

Now, we can summarize the results:
- Lemon juice: Turns blue litmus red (acid).
- Acetic acid: Turns blue litmus red (acid).
- Sodium hydroxide: Does not turn blue litmus red (base).
- Hydrochloric acid: Turns blue litmus red (acid).

**Conclusion**: The solution that will not turn blue litmus red is **Sodium Hydroxide (NaOH)**.

### Final Answer:
**Sodium Hydroxide (NaOH)**

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