CHAPTER 2 ACIDS, BASES AND SALTS
1.
A sample of
soil is mixed with water and allowed to settle. The clear supernatant solution turns the pH paper yellowish-orange. Which of the following would change
the colour of this pH paper greenish-blue?
(i) Lemon juice
(ii) vinegar
(iii) common salt
(iv) antacid
2.
Which of the following salt does
not contain water of crystallization?
(i) Blue vitriol
(ii) Baking soda
(iii) Washing soda
(iv) Gypsum
FILL IN THE BLANKS
3.
is a natural indicator whereas is a
synthetic indicator.
4.
The acid and base present in sodium acetate
are and respectively.
5. is called king of chemicals.
ONE MARK QUESTIONS
6.
Name the substance obtained by
the action of chlorine on dry slaked lime.
7.
In addition to sodium
hydrogen carbonate baking powder contains
a substance X. Name the substance X.
8. How many molecules of water of crystallization are present in washing soda and POP
ASSERTIONS AND REASONS
For the question numbers 10, 11 and 12, two statements are given- one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and
(d) as given below:
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
9. Assertion: Baking powder is used in making cake instead of using baking soda.
Reason: Baking powder contains tartaric acid which reacts with sodium carbonate and removes bitter taste.
10.
Reason:The pH of a solution is inversely proportional to the concentration of hydrogen ions in it.
11. Assertion: The aqueous solution of glucose and alcohol does not show acidic character.
Reason: Aqueous solutions of glucose and alcohol do not produce hydrogen ions.
THREE MARK QUESTIONS
12. How can you prepare sodium hydroxide? Name the products formed on cathode and anode. Write one use of each by-product formed in the above reaction.
13. A substance X is used as a building material and is insoluble in water. When reacted with dilute HCl, it produces a gas that turns lime-water milky. Predict the substance and write the chemical equations involved
14. Give a reason for the following :
(i) Ammonia is a base but does not contain a hydroxyl group.
(ii) Milk of Magnesia
is used by a person suffering from
acidity.
(iii) Sodium hydroxide
cannot be kept in aluminium containers.
15. (a) Write an equation for the reaction of iron with steam. Name the compound of iron obtained
(b)A small amount of copper oxide is taken in a beaker and dil. HCl is added slowly while stirring
(i) What is the colour of the solution obtained?
(ii) What happens to copper oxide during the reaction?
FIVE MARK QUESTION
16. (a) A liquid has a pH less than 7 which represents an acidic solution.
(i) State the nature of the solution, if its pH increases from 7 to 14.
(ii) Mention the ion whose concentration increases with the increase in pH value.
(iii) Suggest a method that is generally used for measuring pH value.
(b)A student collected two samples of dil HCl and distilled water in a separate test tube. She forgot to label the tubes. Both samples are colourless. The solution of litmus, phenolphthalein and lime water is available to her.
(i) How will she distinguish between the two samples?
17. (i) What is the chemical name of the Plaster of Paris?
(ii) Write the chemical formula of plaster of Paris in two ways.
(iii) What happens when Plaster of Paris comes in contact with moisture? Also support your answer with the help of chemical equation.
(iv) Write the two uses of the Plaster of Paris.
18. Demonstrate with the help of an experiment how acidic solution conducts electricity.
(i) If acetic acid and hydrochloric acid of the same concentration are taken, which of the two is stronger acid and why?
(ii) How the strength of alkali solution is will be affected if sodium hydroxide added to it?
19. CASE- STUDY
Answer question numbers 20(a) to 20(d) based on your understanding of the following paragraph and the related studied concepts.
Sunita was learning to bake cakes. She added the ingredients according to the recipes and placed them in the oven. When the cake was ready she took it out from the oven. She was surprised as the cake was hard instead of soft and fluffy.
(a) What is the
probable reason that the cake was not fluffy?
(b) What ingredient did she miss adding while preparing the cake?
(c) Write a chemical reaction to show how this ingredient makes the cake fluffy?
(d)What is the chemical constituent of this ingredient?