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Which reagent is commonly used in the Fehling's test to distinguish between alkanals and alkanones?
- a)Sodium hydroxide
- b)Ammonium hydroxide
- c)Copper(II) sulfate
- d)Potassium iodide
Correct answer is option 'C'. Can you explain this answer?
Most Upvoted Answer
Which reagent is commonly used in the Fehlings test to distinguish bet...
Fehling's test involves the use of Fehling's solution, which contains copper(II) sulfate. The alkanal or alkanone reacts with the copper(II) ions, leading to the reduction of copper(II) ions to copper(I) oxide, which appears as a colored precipitate.
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Which reagent is commonly used in the Fehlings test to distinguish bet...
The correct answer is option C) Copper(II) sulfate.
Explanation:
The Fehling's test is a chemical test used to distinguish between aldehydes (alkanals) and ketones (alkanones). It is based on the ability of aldehydes to be oxidized to carboxylic acids by an oxidizing agent, while ketones cannot be oxidized further.
In the Fehling's test, a solution of Fehling's reagent is used. Fehling's reagent is a mixture of two solutions - Fehling's A and Fehling's B.
Fehling's A is a solution of copper(II) sulfate (CuSO4). Copper(II) sulfate is blue in color.
Fehling's B is a solution of potassium tartrate and sodium hydroxide. It is colorless.
When Fehling's A and Fehling's B are mixed together, a deep blue solution is formed. This solution is capable of oxidizing aldehydes.
During the test, the aldehyde or ketone is heated with Fehling's reagent. If an aldehyde is present, it will be oxidized to a carboxylic acid. As a result, the blue solution of Fehling's reagent will be reduced to form a red precipitate of copper(I) oxide (Cu2O). This indicates a positive test for aldehydes.
On the other hand, if a ketone is present, it cannot be further oxidized. Therefore, the Fehling's reagent remains blue, indicating a negative test for ketones.
In summary, the presence of copper(II) sulfate in Fehling's reagent is essential for the oxidation of aldehydes and the formation of a red precipitate, which allows the distinction between aldehydes and ketones. Thus, option C) Copper(II) sulfate is the correct answer.
Explanation:
The Fehling's test is a chemical test used to distinguish between aldehydes (alkanals) and ketones (alkanones). It is based on the ability of aldehydes to be oxidized to carboxylic acids by an oxidizing agent, while ketones cannot be oxidized further.
In the Fehling's test, a solution of Fehling's reagent is used. Fehling's reagent is a mixture of two solutions - Fehling's A and Fehling's B.
Fehling's A is a solution of copper(II) sulfate (CuSO4). Copper(II) sulfate is blue in color.
Fehling's B is a solution of potassium tartrate and sodium hydroxide. It is colorless.
When Fehling's A and Fehling's B are mixed together, a deep blue solution is formed. This solution is capable of oxidizing aldehydes.
During the test, the aldehyde or ketone is heated with Fehling's reagent. If an aldehyde is present, it will be oxidized to a carboxylic acid. As a result, the blue solution of Fehling's reagent will be reduced to form a red precipitate of copper(I) oxide (Cu2O). This indicates a positive test for aldehydes.
On the other hand, if a ketone is present, it cannot be further oxidized. Therefore, the Fehling's reagent remains blue, indicating a negative test for ketones.
In summary, the presence of copper(II) sulfate in Fehling's reagent is essential for the oxidation of aldehydes and the formation of a red precipitate, which allows the distinction between aldehydes and ketones. Thus, option C) Copper(II) sulfate is the correct answer.
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Which reagent is commonly used in the Fehlings test to distinguish between alkanals and alkanones?a)Sodium hydroxideb)Ammonium hydroxidec)Copper(II) sulfated)Potassium iodideCorrect answer is option 'C'. Can you explain this answer?
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