WORKSHEET 1, CH 5 (CLASS 7)

Question 1
(a) The most commonly used natural indicator is__________________________and is extracted from______________________________
(b) Aqueous solution of baking soda is bitter in taste and feels soapy on touching because it contains______________________________
(c) __________________are used to test whether a substance is acidic or basic in nature.
(d) ____________________change their colour when added to a solution containing an acidic or basic substance.
(e) Lemon juice, orange juice taste sour because they contain_______________________
(f) The solutions which do not change the colour of either blue or red litmus are called ____________________solutions.
(g) Turmeric and litmus are _________ acid-base indicators..
(h) In neutralization reaction heat is always___________________________________.
(i) Salts may be____________________________or_____________________in nature.
(j) Chemically milk of magnesia is______________and baking soda is_______________
(k) China rose indicator turns__________________________solution to dark pink and______________________solution to green
(l) The correct way of making a solution of acid in water is to _________

Question 2
Sodium bicarbonate is commonly called
(a) Lime water
(b) Slaked lime
(c) Washing soda
(d) Baking soda

Question 3
Which of the following statements is correct?
(a) Indicator is a substance that shows different colors in acidic and basic solution.
(b) Turmeric stain on a white shut turns to red when it is washed with soap.
(c) Lime water is a solution of calcium hydroxide.
(d) All the above are correct.

Question 4
Neutralisation reaction is a
(a) physical and reversible change.
(b) physical change that cannot be reversed.
(c) chemical and reversible change.
(d) chemical change that cannot be reversed

Question 5
Which of the following is an acid-base indicator?
(a) Vinegar
(b) Lime water
(c) Turmeric
(d) Baking soda

Question 6
Litmus, a natural dye is an extract of which of the following?
(a) China rose (Gudhal)
(b) Beetroot
(c) Lichen
(d) Blue berries (Jamun)

Question 7
Write the name of two indicators which occur naturally.

Question 8
What is the test for acids and bases using litmus paper?

Question 9
What name is given to those substances which do not change the colour of either red or blue litmus paper?

Question 10
Name the acid present in lemon juice and tomato.