Q1. What will be formed when propanone reacted with sodium hydrogensulphite?

There is white precipitate is the resulting solution . Is it sodium carbonate?

Q2. What are the difference in the products bewteen the reaction of ethanal and propanone reacting with 2,4-dinitrophenylhydrazine?
The resulting solution are both yellow and orange precipitate is formed . It seems that there are some different in the shape of precipitate.

Q3. What is the polymer formed when ethanal reacted with sodium hydroxide solution?

Q4. What will be formed when ethanal reacted with acidified dichromate(VI) ?
Why is the resulting solution green ?

Q5. What will be formed when propanone reacted with Fehling's solution?The resulting solution is yellow and green precipitate is formed . Is that precipitate copper carbonate?

Q6.What are the difference in products between the reaction of ethanal and propanone reacting with iodine solution and sodium hydroxide solution ?The resulting solution of ethanal one is orange while the other is very pale yellow or nearly colorless.Both of them give yellow precipitate . Are the precipitates the same?

Q7. Which reagent should i use to test for carbonyl compound?

1. The product is an addition compound in which the =O becomes OH and the central carbon atom is linked to the sulfite group. No special IUPAC name as far as I know.

2. The products are the 2,4-dinitrophenylhydrazone of propanone or 2,4-dinitrophenylhydrazone of ethanal. The important difference between the tqo compounds is the melting point of each.
3. No polymer of ethanal is formed under the conditions you described.
4. Ethanal can be oxidized to acetic acid by chromic acid. Green Cr^3+(aq) ions are also produced.
5. Ketones do not react with Fehling's solution, except for alpha hydroxy ketones.
6. Look up the Iodoform Reaction for methyl ketones.
7. Go back to your 2nd question. That should give you some ideas.

thanks a lot !!!

A1. When propanone reacts with sodium hydrogensulphite, it forms a compound called sodium bisulfite adduct. This adduct appears as a white precipitate in the resulting solution. It is not sodium carbonate.

To confirm the identity of the precipitate, you can perform a simple test using hydrochloric acid. If the precipitate dissolves upon addition of hydrochloric acid, then it is sodium carbonate. If it does not dissolve and remains as a white solid, then it is sodium bisulfite adduct.

A2. The reaction of ethanal and propanone with 2,4-dinitrophenylhydrazine (DNPH) forms a derivative known as a 2,4-dinitrophenylhydrazone, which appears as a yellow-orange precipitate.

The difference in the shape of the precipitate may indicate variations in the structure of the hydrazone formed by each ketone. Ethanal forms a more elongated or needle-shaped precipitate, while propanone forms a more rounded or block-shaped precipitate. This difference is due to the structural differences between the two ketones.

A3. When ethanal reacts with sodium hydroxide solution, it undergoes a condensation reaction to form a polymer called polyvinyl alcohol (PVA). This polymer is formed from repeated units of the ethanal molecule joined together through oxygen atoms.

A4. When ethanal reacts with acidified dichromate(VI), it undergoes an oxidation reaction to form acetic acid. The resulting solution appears green because of the presence of the chromium ion in the dichromate(VI) reagent. The green color is characteristic of chromium compounds.

A5. When propanone reacts with Fehling's solution, the resulting solution turns yellow and a green precipitate is formed. The precipitate is not copper carbonate.

The green precipitate formed in this reaction is actually copper(I) oxide (Cu2O). Fehling's solution contains copper(II) ions, which are reduced to form copper(I) oxide by the propanone. The yellow color in the solution is due to the presence of the oxidized propanone.

A6. The reactions of ethanal and propanone with iodine solution and sodium hydroxide solution form the same product, which is a yellow precipitate called iodoform.

However, there are some differences in the appearance of the resulting solutions. The solution of ethanal with iodine appears orange, while the solution of propanone with iodine appears very pale yellow or nearly colorless. This difference may be due to the varying amounts of iodine used in each reaction or the reaction conditions.

A7. To test for carbonyl compounds, you can use a reagent called 2,4-dinitrophenylhydrazine (DNPH). This reagent reacts with the carbonyl group to form a distinctive yellow-orange precipitate called a 2,4-dinitrophenylhydrazone. The formation of this precipitate confirms the presence of a carbonyl compound.

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