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Question
In order to study saponification reaction, we first prepare 20% solution of sodium hydroxide. If we record the temperature of this solution just after adding sodium hydroxide flakes to water and also test its nature using litmus, it may be concluded that the process of making this solution is
(A) exothermic and the solution is alkaline
(B) endothermic and the solution is alkaline
(C) endothermic and the solution is acidic
(D) exothermic and the solution is acidic
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Solution
Dissolution of sodium hydroxide in water evolves large amount of heat. Thus, it is an exothermic reaction. Since sodium hydroxide is a base, its solution in water will be alkaline when tested with litmus paper (red litmus turns blue).
Hence, the correct option is A.
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RELATED QUESTIONS
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
Vinegar is a solution of about:
(a) 5 to 8 per cent ethanoic acid in alcohol
(b) 5 to 8 per cent ethanoic acid in water
(c) 50 to 80 per cent ethanoic acid in water
(d) 50 to 80 per cent ethanoic acid in alcohol
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Vinegar is a solution of about ________per cent ________in water.
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Ethyl chloride to Ethyl alcohol
Ethanoic acid _________.
Choose the correct alternative and rewrite the following:
Some acetic acid is treated with solid NaHCO3, the resulting solution will be _________________.
Give the balanced chemical equation of the following reaction:
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A spatula full of sodium carbonate is taken in a test tube and 2 mL of dilute ethanoic acid is added to it.
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Name the oxidising agent used in the conversion of ethanol to ethanoic acid.
Give the balanced chemical equation of the following reaction:
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