Monday, July 27, 2020

WORKSHEET 3, CH 5, CLASS 7

Q1. Fill in the cross word given as Figure 5.2 with the help of the clues provided.

Acids, Bases and Salts
  • (2) The solution which does not change the colour of either red or blue litmus.
  • (4) Phenolphthalein gives pink colour in this type of solution.
  • (7) Colour of blue litmus in lemon juice.
Down
  • (1) It is used to test whether a substance is acidic or basic.
  • (3) It is a natural indicator and gives pink colour in basic solution.
  • (5) Nature of ant’s sting.
  • (6) It is responsible for increase in temperature during a neutralisation reaction.
Q2. 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.

Q3. Form a sentence using the following words – baking soda, antbite, moist, effect, neutralised, rubbing.

Q4. Match the substances in Column I with those in Column II.
Acids, Bases and Salts

Q5. Fill 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.

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