What will be the colour of red and blue litmus paper when they are dipped in a suspension of rust and water?

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Solution

Litmus paper is an indicator that identifies if a substance is basic or acidic. Red litmus paper turns blue in basic solution and remains unaffected in acidic solution. Blue litmus paper turns red in acidic solution and remains unaffected in basic solution.

Metal oxides are generally basic in nature. Rust is hydrated iron oxide. It is formed when iron reacts with oxygen and moisture. Therefore, rust is basic in nature. So the colour of red litmus paper will turn blue and the colour of blue litmus paper will remain unaffected when they are dipped in a suspension of rust and water.

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Similar questions

The ‘green rust’ of copper is scrapped and dissolved in water. When litmus paper is dipped in it, what will be the change in colour ?

When blue litmus paper is dipped into the water, the colour of litmus paper remains same. Similarly, when a red litmus paper is dipped into the water, the colour remains same. By the above observation, we can conclude that:

When a red litmus paper is dipped in the aqueous solution of $X$ there is no change in colour.
When a blue litmus paper is dipped in the same solution it turns red.
Which among the following options can be the chemical $X$ ?

Q. Read the following statements:
I. When a red litmus paper is dipped into reaction mixture of a saponification reaction, it turns blue and the reaction is exothermic.
II. When a blue litmus paper is dipped into reaction mixture of a saponification reaction, its colour does not change and the reaction is exothermic.
III. When a red litmus paper is dipped into reaction mixture of a saponification reaction, its colour does not change and the reaction is endothermic.
IV. When a blue litmus paper is dipped into reaction mixture of a saponification reaction, its colour does not change and the reaction is endothermic.
Which of the above statements are correct?

Read the following statements

(i) When a red litmus paper is dipped into reaction mixture of a saponification reaction, it turns blue and the reaction is exothermic.

(ii) When a blue litmus paper is dipped into reaction mixture of a saponification reaction, its colour does not change and the reaction is exothermic

(iii) When a red litmus paper is dipped into reaction mixture of a saponification reaction, its colour does not change and the reaction is endothermic.

(iv) When a blue litmus paper is dipped into reaction mixture of a saponification reaction, its colour does not change and the reaction is endothermic.

Which of the above statements are correct

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