EASY
7th CBSE
IMPORTANT
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Phenolphthalein gives  colour with lime water.

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Important Questions on Acids, Bases and Salts

EASY
7th CBSE
IMPORTANT
NCERT Exemplar Science - Class 7>Chapter 5 - Acids, Bases and Salts>LONG ANSWER QUESTIONS>Q 20
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 two drops of solution 'B' to her test tube and got green colour. Golu added two drops of solution 'C' but could not get any change in colour. Suggest the possible cause for the variation in their results.
HARD
7th CBSE
IMPORTANT
NCERT Exemplar Science - Class 7>Chapter 5 - Acids, Bases and Salts>LONG ANSWER QUESTIONS>Q 21

Fill in the cross word given as in the figure with the help of the clues provided.

Question Image

Across

(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 the increase in temperature during a neutralisation reaction.

EASY
7th CBSE
IMPORTANT
NCERT Exemplar Science - Class 7>Chapter 5 - Acids, Bases and Salts>LONG ANSWER QUESTIONS>Q 22
A farmer was unhappy because of his low crop yield. He discussed the problem with an agricultural scientist and realised that the soil of his field was either too acidic or too basic. What remedy would you suggest the farmer to neutralise the soil?
EASY
7th CBSE
IMPORTANT
NCERT Exemplar Science - Class 7>Chapter 5 - Acids, Bases and Salts>LONG ANSWER QUESTIONS>Q 23
You are provided with four test tubes containing sugar solution, baking soda solution, tamarind solution, salt solution. Write down an activity to find the nature (acidic/basic/neutral) of each solution.
EASY
7th CBSE
IMPORTANT
NCERT Exemplar Science - Class 7>Chapter 5 - Acids, Bases and Salts>LONG ANSWER QUESTIONS>Q 24

You are provided with three test tubes A, B and C as shown in figure with different liquids. What will you observe when you put

(a) a piece of blue litmus paper in each test tube.

(b) a piece of red litmus paper in each test tube.

(c) a few drops of phenolphthalein solution to each test tube.

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EASY
7th CBSE
IMPORTANT
NCERT Exemplar Science - Class 7>Chapter 5 - Acids, Bases and Salts>LONG ANSWER QUESTIONS>Q 25
Paheli observed that most of the fish in the pond of her village were gradually dying. She also observed that the waste of a factory in their village is flowing into the pond which probably caused the fish to die. (a) Explain why the fish were dying. (b) If the factory waste is acidic in nature, how can it be neutralised?
MEDIUM
7th CBSE
IMPORTANT
NCERT Exemplar Science - Class 7>Chapter 5 - Acids, Bases and Salts>LONG ANSWER QUESTIONS>Q 26
Explain two neutralisation reactions related to daily life situation.