Complete the following table: S. No Solution Indicator Initial colour of indicator Final colour of indicator 1 Milk of magnesia Phenolphthalein 2 Vinegar Red 3 Shampoo Yellow 4 Soap solution China Rose 5 Sodium hydroxide Pink 6 Slaked lime Purple Green

Completed table is as follows: Milk of magnesia is basic. Therefore, it is pink in colour. Vinegar is weakly acidic, therefore, it turns blue litmus to red. The shampoo is basic; therefore, natural indicator turmeric changes its colour from yellow to red. Soap solution contains sodium hydroxide, which is a base, and it turns china rose to green. Sodium hydroxide is a base, and hence phenolphthalein turns into pink. Slaked lime is calcium hydroxide, which is a base and it turns china grass from purple to green. S. No Solution Indicator Initial colour of indicator Final colour of the indicator 1 Milk of magnesia Phenolphthalein Colourless Pink 2 Vinegar Blue litmus paper Purple Red 3 Shampoo Turmeric Yellow Red 4 Soap solution China Rose Purple Green 5 Sodium hydroxide Phenolphthalein Colourless Pink 6 Slaked lime China rose Purple Green

E M B I B E

WOW! SCIENCE Hands-on Learning in SCIENCE 7>Chapter 8 - Acids, Bases and Salts>EVALUATE>Q 3

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7th CBSE

IMPORTANT

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The pH values of five solutions A, B, C, D and E are given below:

Solution A B C D E

$p H$ $6$ $8$ $1$ $7$ $14$

Which solution is: Strongly acidic

Important Questions on Acids, Bases and Salts

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IMPORTANT

WOW! SCIENCE Hands-on Learning in SCIENCE 7>Chapter 8 - Acids, Bases and Salts>EVALUATE>Q 3

The pH values of five solutions A, B, C, D and E are given below:

Solution	A	B	C	D	E
$p H$	$6$	$8$	$1$	$7$	$14$

Which solution is: Weakly alkaline?

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7th CBSE

IMPORTANT

WOW! SCIENCE Hands-on Learning in SCIENCE 7>Chapter 8 - Acids, Bases and Salts>EVALUATE>Q 3

The pH values of five solutions A, B, C, D and E are given below:

Solution	A	B	C	D	E
$p H$	$6$	$8$	$1$	$7$	$14$

Which solution is: Weakly acidic?

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WOW! SCIENCE Hands-on Learning in SCIENCE 7>Chapter 8 - Acids, Bases and Salts>EVALUATE>Value and life skills

We all know that the chemicals in our laboratory are very dangerous. Thus, safety measures need to be adopted while working in a lab. List down some of these measures and follow them when you visit your laboratory.

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7th CBSE

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WOW! SCIENCE Hands-on Learning in SCIENCE 7>Chapter 8 - Acids, Bases and Salts>EVALUATE>Q 1

Which one of the following is the weakest base?

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WOW! SCIENCE Hands-on Learning in SCIENCE 7>Chapter 8 - Acids, Bases and Salts>EVALUATE>Q 2

Which of the following salts is used in photography for developing films?

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WOW! SCIENCE Hands-on Learning in SCIENCE 7>Chapter 8 - Acids, Bases and Salts>WORKSHEET>Q A

Solve the following crossword.

Across

1. This acid is present in oranges
3. Turmeric paper turns to this colour when dipped in a basic medium
5. This is a solution of nitric acid and hydrochloric acid in the ratio $1 : 3$
7. Magnesium hydroxide is used as
8. This is known as king of acids

Down

2. This acid is present in grapes
4. Bitter substances contain this chemical
6. Water soluble bases

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7th CBSE

IMPORTANT

WOW! SCIENCE Hands-on Learning in SCIENCE 7>Chapter 8 - Acids, Bases and Salts>WORKSHEET>Q B

Complete the following table:

S. No	Solution	Indicator	Initial colour of indicator	Final colour of indicator
1	Milk of magnesia	Phenolphthalein
2	Vinegar			Red
3	Shampoo		Yellow
4	Soap solution	China Rose
5	Sodium hydroxide			Pink
6	Slaked lime		Purple	Green