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प्रश्न
A student puts a drop of acetic acid first on a blue litmus paper and then on a red litmus paper. He would observe that
(A) the red litmus paper turns colourless and there is no change in the blue litmus paper.
(B) the red litmus paper turns blue and the blue litmus paper turns red.
(C) there is no change in the red litmus paper and the blue litmus paper turns red.
(D) there is no change in the blue litmus paper and the red litmus paper turns blue.
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उत्तर
Being an acid, acetic acid turns blue litmus paper red. Thus, on putting a drop of acetic acid on blue and red litmus papers, there is no change in the red litmus paper, while the blue litmus paper turns red.
Hence, the correct option is C.
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संबंधित प्रश्न
A student puts a drop of reaction mixture of a saponification reaction first a blue litmus paper and then on a red litmus paper. He may observe that:
(a) There is no change in the blue litmus paper and the red litmus paper turns white.
(b) There is no change in the red litmus paper and the blue litmus paper turns red.
(c) There is no change in the blue litmus paper and the red litmus paper turns blue.
(d) No change in colour is observed in both the litmus papers
For preparing soap in the laboratory we require an oil and a base. Which of the following combinations of an oil and a base would be best suited for the preparation of soap?
(a) Castor oil and calcium hydroxide
(b) Turpentine oil and sodium hydroxide
(c) Castor oil and sodium hydroxide
(d) Mustard oil and calcium hydroxide
Consider the following comments about saponification reactions:
I. Heat is evolved in these reactions.
II. For quick precipitation of soap, sodium chloride is added to the reaction mixtures.
III. Saponification reactions are a special kind of neutralisation reactions.
IV. Soaps are basic salts of long-chain fatty acids.
The correct comments are
(a) I, II and III
(b) II, III and IV
(c) I, II and IV
(d) Only I and IV
Give a reason for Conductivity of dilute hydrochloric acid is greater than that of acetic acid
Draw the structures for the following compounds of Propanoic acid.
Name the functional group present in the following compound:
C2H5CHO
A student takes Na2CO3 powder in a test tube and pours some drops of acetic acid over it. He observes:
(A) no reaction in the test tube
(B) colourless gas with pungent smell
(C) bubbles of a colourless and odourless gas
(D) white fumes with smell of vinegar
Why is pure acetic acid also known as glacial acetic acid?
Ethanoic acid reacts with the basic salt, sodium carbonate, to form a salt, named ______, water and carbon dioxide gas.
A spatula full of sodium carbonate is taken in a test tube and 2 mL of dilute ethanoic acid is added to it.
Write a chemical equation for the reaction.
