Classification of Indicators

Q.

When does the colour of blue litmus turn red?

Q.

1. A strip of absolutely clear cloth is sprayed with onion juice. The strip is then rubbed with

few drops of hydrochloric acid. Will the strip smell like onion? Give a reason for your answer.

Q.

Higher the pH value of a solution, the more ___ it is.

Q. Smell of freshly cut onion is not detectable when HCl is added to it.

1. True
2. False

Q.

Which of the following cannot act as an indicator?

1. Methyl chloride

2. Methyl orange

3. Turmeric

4. Phenolphthalein

Q.

You are given two solutions A and B. The pH of solution A is 6 and the pH of solution B is 8. Which solution is acidic and which is basic?

Q. Olfactory indicators like vanilla and clove produce a pungent smell in an acidic medium.

1. True
2. False

Q.

Red cabbage indicator turns _______ in basic solutions.

1. Green

2. Blue

3. Pink

4. Purple

Q. Red cabbage extract turns pink on addition of an acid.

1. True
2. False

Q. Olfactory indicators change their on addition of an acid or a base to it.

1. state
2. colour
3. odour

Q. Which of the following are natural indicators?

1. Phenolphthalein
2. China rose
3. Turmeric
4. Methyl orange
5. Litmus
6. Onion
7. Baking soda
8. Red cabbage

Q. Acids and bases can be distinguished using indicators.

1. True
2. False

Q. Which one of the following can be used to check the pH of the salt solution?

1. Turmeric paper
2. Litmus paper
3. Filter paper
4. Butter paper

Q. Match the following indicators to the respective colour change in the acidic or basic medium:

1. Red (acidic)
2. Yellow (basic)
3. Colourless (acidic)
4. Green (basic)

Q. Red cabbage extract is a synthetic indicator.

1. False
2. True

Q.

How does consuming sugarless chewing gum help prevent tooth decay?

As a responsible citizen, how do you intend to dispose of the chewing gum after chewing it?

Q. Smell of clove cannot be characterized in:

1. acidic medium
2. basic medium
3. neutral medium
4. both A and B

Q. One student examines the properties of the substance in the laboratory. Aqueous solution of this substance converts blue litmus paper into the red. Identify the substance.
(P) Lemon Juice (Q) Tomato Juice (R) Washing Soda

1. P and R
2. Q and R
3. P, Q, and R all
4. P and Q

Q. Choose the correct pair from the following.

1. Onion
2. Litmus
3. Visual indicator
4. Olfactory indicator
5. Synthetic indicator
6. Methyl orange

Q. Which of the following indicator gives more than two colours?

1. Phenolphthalein
2. Turmeric
3. Universal indicator
4. Methyl orange

Q. Visual indicators change their on addition of an acid or a base.

1. state
2. colour
3. odour

Q. Litmus is a indicator which is obtained from ​​.

1. fungi
2. natural
3. synthetic
4. lichens

Q.

A curry made of turmeric (haldi, an indicator of acid or base) falls on a white table cloth. when we wash it with acid or a base, there it no indication on it, whereas if used differently shows change in colour. why so?