Visual Indicators

Q.

Describe the morning scene in five sentences

Q.

Question 11
Consider the following statements:

Which of these statements are correct?

(a) Both acids and bases change colour of all indicators.
(b) If an indicator gives a colour change with an acid, it does not give a change with a base.
(c) If an indicator changes colour with a base, it does not change colour with an acid.
(d) Change of colour in an acid and a base depends on the type of the indicator.

Which of these statements are correct?
(i) All four
(ii) a and d
(iii) b and c
(iv) only d

Q. Methyl orange gives ______ colour in an acidic solution.

1. yellow
2. green
3. white
4. red

Q.

Why does turmeric changes colour into red when we put lemon juice in it

Q.

Distilled water changes the colour of which of the following indicators?

1. Red Litmus

2. Blue litmus

3. Turmeric powder solution

4. No change in any indicator

Q.

Choose the correct option for the given statements.

Statement-I: Titration of a strong acid with a weak base uses methyl orange as an indicator.

Statement-II: Titration of a weak acid with a strong base doesnt uses phenolphthalein as an indicator.

1. Statement I is correct and Statement II is correct

2. Statement I is correct and Statement II is incorrect

3. Statement I is incorrect and Statement II is incorrect

4. Statement I is incorrect and Statement II is correct

Q.

Dorji has a few bottles of soft drinks in his restaurant. But, unfortunately, these are not labelled. He has to serve the drinks on the demand of customers. One customer wants an acidic drink, another wants a basic one and the third one wants a neutral drink. How will Dorji decide which drink is to be served to whom?

Q. What will happen if you mix an indicator with another indicator?

Q.

Sodium hydroxide turns phenolphthalein solution to-

1. pink
2. yellow
3. colourless
4. orange

Q.

Why do visual indicators show a a change in colour when introduced to an acidic or basic or medium

Q.

Rearrange the jumbled letters to obtain the name of an indicator.

MUSLIT --> ___

Q.

How do earthworms breathe?

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

1. state
2. colour
3. odour

Q.

An indicator responds to acid or base by:

1. change in smell

2. change in temperature

3. change in color

4. Both A and C

Q.

Give two tests of hydrogen.

Q. name an indicator which is colorless in acid or neutral solution but turns deep blue color in basic solution

Q. Question 7
Dorji has a few bottles of soft drink in his restaurant. But, unfortunately, these are not labelled. He has to serve the drinks on the demand of customers. One customer wants an acidic drink, another wants basic and third one wants a neutral drink. How will Dorji decide which drink is to be served to whom?

Q.

Substances that are used to determine whether a particular substance is an acid or a base are called __________ .

1. reagent

2. catalyst

3. salt

4. indicator

Q. Which of the following pairs of indicator and its colour in given medium are correct?

1. Litmus - Blue in acidic medium
2. China rose - Dark pink in acidic medium
3. Phenolphthalein - Pink in basic medium
4. Litmus - Red in basic medium

Q. Complete the table given below with the correct colours of different indicators in acidic, basic and neutral solutions.

1. (i) – Green; (ii) – Yellow; (iii) – Blue; (iv) - Colourless
2. (i) – Red; (ii) – Pink; (iii) – Yellow; (iv) - Green
3. (i) – Blue; (ii) – Pink; (iii) – Yellow; (iv) - Green
4. (i) – Red; (ii) – Pink; (iii) – Green; (iv) - Colourless

Q. Dorji has a few bottles of soft drink in his restaurant. But, unfortunately, these are not labelled. He has to serve the drinks on the demand of customers. One customer wants acidic drink, another wants basic and third one wants neutral drink. How will Dorji decide which drink is to be served to whom?

Q. (a) Dorji has a few bottles of soft drink in his restaurant. But, unfortunately, these are not labelled. He has to serve the drinks on the demand of customers. One customer wants acidic drink, another wants basic and third one wants neutral drink. How will Dorji decide which drink is to be served to whom? [3 marks]

(b) Boojho, Paheli and their friend Golu were provided with a test tube each containing China rose solution which was pink in colour. Boojho added two drops of solution ‘A’ in his test tube and got dark pink colour. Paheli added 2 drops of solution ‘B’ to her test tube and got green colour. Golu added 2 drops of solution ‘C’ but could not get any change in colour. Suggest the possible cause for the variation in their results. [2 marks]

Q. Dorji has a few bottles of soft drink in his restaurant. But, unfortunately, these are not labelled. He has to serve the drinks on the demand of customers. One customer wants acidic drink, another wants basic and third one wants neutral drink. How will Dorji decide which drink is to be served to whom?

Q.

Sodium hydroxide turns phenolphthalein solution to-

1. pink
2. yellow
3. colourless
4. orange