Indicators and Universal Indicator

Q. Olfactory Indicators indicate presence of acid or base by change in ______.

1. colour
2. smell
3. temperature
4. taste

Q.

Question 13

State whether the following statements are true or false. Correct the false statements.
(a) All substances are either acidic or basic.
(b) A compound if acidic will turn all indicators red
(c) Lime water turns red litmus blue
(d) Common salt dissolved in water turns blue litmus red
(e) Phenolphthalein is a natural indicator
(f) Calamine can be used to treat ant’s sting
(g) Lemon water is basic in nature

Q.

State the colour of phenolphthalein in soap solution.

Q.

Which of the following cannot be used as an acid-base indicator?

1. Chilly powder

2. Whitepaper

3. Carbon powder

4. Liquid blue

Q. Natural Indicators turn acids which colour

Q.

Which of the following solution will turn red hibiscus paper to blue?

1. Vinegar

2. Water

3. Buttermilk

4. Soap

Q.

Phenolphthalein is a synthetic indicator and its colours in acidic and basic solutions, respectively are

1. red and blue

2. blue and red

3. pink and colourless

4. colourless and pink

Q.

Which of these can be used to distinguish acids from bases?

1. Turmeric

2. Vinegar

3. Lime water

4. Baking Soda

Q.

A solution undergoes several colour changes over a wide range of pH. What is the solution called?

1. Litmus solution

2. Phenolphthalein solution

3. Phenyl methyl solution

4. Universal indicator

Q.

Which of the following can act as the acid-base indicator?

1. Phenolphthalein

2. Methyl chloride

3. Methyl orange

4. Turmeric

Q.

Phenolphthalein is

1. yellow in acidic medium, pink in basic medium.

2. pink in acidic medium, colorless in basic medium.

3. colorless in acidic medium, pink in basic medium.

4. pink in acidic medium, yellow in basic medium.

Q.

Yellow spots of turmeric on clothes turn brown when they come in contact with water and soap. Why?

Q.

Manushree was observing a sample of adulterated arhar dal with metanil yellow.What colour appears when hydrochloride acid is added to the sample.

1. Red

2. Blue

3. Pink

4. Yellow

Q.

Phenolphthalein shows blue color in acidic medium.

1. True
2. False

Q.

Is distilled water acidic, basic or neutral? How would you verify it?

Q. Study the following table carefully and identify X, and Y.​

Substance	Tumeric Solution	Indicator (Y)
Curd	Yellow	Red
X	Red	Blue
Toothpaste	Red	Blue

1. X: Soap; ​Y: China rose
2. X: Vinegar; ​Y: Litmus solution​
3. X: Soap; ​Y: Litmus solution
4. X: Tamarind; ​Y: Phenolphthalein​

Q.

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

HCINA ORSE

__

Q.

Distilled water is

1. Can't be determined

2. Basic

3. Neutral

4. Acidic

Q.

What will you observe when a drop of phenolphthalein is added?

Q. When phenolphthalein is added to a soapy solution, it is observed that it turns

1. Red

2. Blue
3. Pink
4. Orange

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. Which of the given observation is correct concerning the given scenario?

Test tube: 10 mL of sodium hydroxide mixed with 2 mL of hydrochloric acid
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1. Addition of red cabbage juice to the test tube will give a reddish coloured solution.
2. Addition of phenolphthalein to the test tube will give a pink coloured solution.
3. Addition of red litmus extract to the test tube will give a colourless solution.
4. Addition of turmeric to the test tube will give a black coloured solution.

Q.

Indicators are substances that indicates whether the substance is acidic in nature.

1. False

2. True

Q.

Which of the following substance will give a pale yellow colour when tested with methyl orange indicator?

1. Lactic acid

2. Hydrochloric acid

3. Sodium hydroxide

4. Lime water

Q. Methyl orange turns _____ colour in basic solution.

1. blue
2. yellow
3. pink
4. red

Q. Consider the following statements:
(i) Both acids and bases change colour of all indicators.
(ii) If an indicator gives a colour change with an acid, it does not give a change with a base.
(iii) If an indicator changes colour with a base, it does not change colour with an acid.
(iv) Change of colour in an acid and a base depends on the type of the indicator.
Which of these statements are correct? [1 mark]

(a) All four
(b) (i) and (iv)
(c) (ii), (iii) and (iv)
(d) Only (iv)