Question

1. What will you observe when : (a) a drop of sodium hydroxide is added to blue litmus ?
(b) a drop of hydrochloric acid is added to China rose indicator
(c) a drop of dilate sulphuric acid is added to red-cabbage juice
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Answer 1

Answer:

(a) A ‘drop of sodium hydroxide’ is added to blue litmus paper remains change.

• Litmus paper is used as an acid base indicator.
• If an acid contact with blue litmus paper than it changes to red colour.
• If a base is contact with red litmus paper than it colour remains.

(b) A ‘drop of hydrochloric acid’ is added to China rose indicator it changes to magenta colour.

• If China rose indicator is added to the acid to turns magenta colour.
• If China rose indicator is added to the base to turns green colour.

(c) A ‘drop of dilate sulphuric acid’ is added to red-cabbage juice and turns to red colour. Therefore, the colour of solution is changes to red.

• If the red-cabbage juice is added to the acid to turns to red colour.

Answer 2

Answer:

(a) A ‘drop of sodium hydroxide’ is added to blue litmus paper remains change.

Litmus paper is used as an acid base indicator.

If an acid contact with blue litmus paper than it changes to red colour.

If a base is contact with red litmus paper than it colour remains.

(b) A ‘drop of hydrochloric acid’ is added to China rose indicator it changes to magenta colour.

If China rose indicator is added to the acid to turns magenta colour.

If China rose indicator is added to the base to turns green colour.

(c) A ‘drop of dilate sulphuric acid’ is added to red-cabbage juice and turns to red.