Question

Q9. Which one of the following can be used as an acid–base indicator

by a visually impaired student?

(a) Litmus

(b) Turmeric

(c) Vanilla essence

(d) Petunia leaves

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Answer 1

Answer:

C - Vanilla Essence is the correct answer

Explanation:

Vanilla essence is used as an indicator because of its smell which helps visually challenged people to realize the change in pH.

Hope it helps U !!

Answer 2

For an Visulally Impaired student, who is not able to see the change in colour of Indicator in acid or basic solution, he can only detect the type of solution by its smell. Hence, the suitable Indicators would be:

$\large{ \boxed{ \bf{ \pink{Vanilla \: essence\: (C)}}}}$

Explanation:

• Since, Vanilla essence is an olfactory indicator which can change its smell in presence of acid or basic solution.
• Rest, Litmus, Turmeric and Petunia leaves are known for changing their colours.

Explore more!!

Indicators are chemical compounds that indicates the presence of acidic, basic or neutral solution by changing its colour or odour.

• Indicators changing colour are known as Visual Indicators and Indicators changing smell, are known as Olfactory Indicators.
• Litmus - It is a purple dye which we obtained from lichen. It is available in strips or solution. When a blue litmus paper is dipped in acid, it changes its colour into red. And vice-versa in base.
• Turmeric- They are spices used in our kitchens, which is yellow in colour. It remains same in neutral and acidic solution. But, Changes its colour into reddish-brown in basic solution.
• Similarly, Other indicators includes Phenopthalein, Methyl Orange, Red cabbage, China rose etc.

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