Consider the following statements:
(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)
Correct answer: (ii) (a) and (d)
Explanation: Both acids and bases change colour of all indicators and the change of colour in an acid and a base depends on the type of the indicator. Hence, both statements are true.
The different colours showed by some indicators are given below:
Acids | Bases |
a. Acids remains colourless in phenolphthalein indicator b. Acids turn blue litmus to red. c. Acids do not change the colour of turmeric (yellow). d. Acids give a pH of 1-7. | a. Bases gives pink colour in phenolphthalein indicator. b. Bases turn red litmus to blue. c. Bases turn turmeric from yellow to red. d. Bases give a pH of 7-14.
|
[Extra information: Indicators are substances that show acidic or basic behaviour of other substances by showing a change in colour. There are different types of indicators. These are :
Natural indicators like turmeric and litmus.
Synthetic indicators like Methyl orange and phenolphthalein.
Olfactory indicators like onion and vanilla extract.
Universal indicators like pH.]
Related Articles
- (a) What is produced if an acid is added to a base?(b) Why does dry HCl gas not change the colour of dry litmus paper?(c) What colour does phenolphthalein indicator turn when added to an alkali (such as sodium hydroxide)?
- (a) What is an indicator? Name three common indicators.(b) Name the acid-base indicator extracted from lichen. (c) What colour does the turmeric paper turn when put in an alkaline solution?
- (a) While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid?(b) Dry hydrogen chloride gas does not change the colour of dry litmus paper why?
- If turmeric does not change colour in neutral and acid. So how will we know a substance Is neutral or acidic?
- Change colour of an image drawn on an HTML5 canvas element.
- Which of the following statements is correct about an aqueous solution of an acid and of a base?Higher the pH, stronger the acidHigher the pH, weaker the acidLower the pH, stronger the baseLower the pH, weaker the base(a) (i) and (iii)(b) (ii) and (iii)(c) (i) and (iv)(d) (ii) and (iv)
- A student measured the pH values of four solutions A, B, C and D which were found to be 4, 1, 13 and 11 respectively. Which of the following statements are correct about these solutions?(a) A is strong acid and B is weak acid (b) B is strong acid and D is weak base (c) D is strong base and C is weak base (d) C is strong base and A is weak acid (1) (a) and (b) (2) (b) and (c) (3) (c) and (d) (4) (b) and (d)
- Read the following statements:I. When a red litmus paper is dipped into the reaction mixture of a saponification reaction, it turns blue and the reaction is exothermic.II. When a blue litmus paper is dipped into the reaction mixture of a saponification reaction, its colour does not change and the reaction is exothermic.III. When a red litmus paper is dipped into the reaction mixture of a saponification reaction, its colour does not change and the reaction is endothermic.IV. When a blue litmus paper is dipped into the reaction mixture of a saponification reaction, its colour does not change and the reaction is endothermic.Which of the above statements are correct?(a) I and II(b) II and III(c) III and IV(d) I and IV
- Colour is a physical property then how could be change in colour be a chemical change?
- Sodium carbonate is a basic salt because it is a salt of(a) strong acid and strong base(b) weak acid and weak base(c) strong acid and weak base(d) weak acid and strong base
- Why does the colour of copper sulphate solution change when an iron nail is dipped into it?
- Which of the following statements is not correct?(a) All metal carbonates react with acid to give a salt, water and carbon dioxide(b) All metal oxides react with water to give salt and acid(c) Some metals react with acids to give salt and hydrogen(d) Some non-metal oxides react with water to form an acid
- Answer the following questions:-1. Turmeric is(a) an acid (b) a base (c) salt (d) an indicator2. What are indicators? Name two olfactory indicators.3. Name two other natural indicators. How do they behave with acids and bases?
- Fill in the blanks in the following sentences.(a) Lemon juice and vinegar taste _____ because they contain _____.(b) Turmeric and litmus are _____ acid-base indicators.(c) Phenolphthalein gives _____ colour with lime water.(d) When an acidic solution is mixed with a basic solution, they _____ each other forming _____ and water.
- Which of the following statements is correct about an aqueous solution of an acid and of a base?(i) Higher the pH, stronger the acid (ii) Higher the pH, weaker the acid (iii) Lower the pH stronger the base (iv) Lower the pH, weaker the base
Kickstart Your Career
Get certified by completing the course
Get Started