Question

Which one of the following can be used as an acid-base indicator by a visually impaired (blind) student?

• A. Turmeric
• B. Vanilla essence
• C. Methyl orange
• D. Litmus

Hint:

Olfactory indicators (smell-based) for visually impaired:

• Vanilla essence \(\Rightarrow\) Smell disappears in base
• Onion \(\Rightarrow\) Smell destroyed in base
• Clove oil \(\Rightarrow\) Smell changes in acid/base

These are safer and more accessible alternatives to visual indicators.

Answer 1

The Correct Option is B

To determine which option can be used as an acid-base indicator by a visually impaired (blind) student, we need to understand the characteristics of each option given:

1. Turmeric: Turmeric is a natural indicator that changes color in acidic and basic solutions. However, it primarily relies on visual color changes, which are not suitable for visually impaired students.
2. Vanilla essence: Vanilla essence does not rely on visual changes to indicate the acidity or basicity of a solution; instead, it relies on changes in smell. In acidic conditions, the smell of vanilla may be masked or altered, making it a practical indicator for visually impaired individuals.
3. Methyl orange: Methyl orange is a synthetic indicator that changes color at different pH levels. Like turmeric, it primarily depends on visual changes, which are not helpful for visually impaired students.
4. Litmus: Litmus is a well-known indicator that changes color based on the pH of the solution. Similar to turmeric and methyl orange, it is dependent on visual cues.

Based on the explanations above, Vanilla essence is the only option that does not rely on color changes and can be detected through smell, making it suitable for visually impaired students to use as an acid-base indicator.

Therefore, the correct answer is Vanilla essence.

Conclusion: Vanilla essence is suitable for use as an acid-base indicator by a visually impaired (blind) student because it relies on changes in smell rather than visual changes.