Aldehydes And Ketones

(i) Formaldehyde and Acetaldehyde
Test: Schiff’s Reagent Test
- Formaldehyde gives a deep pink colour with Schiff’s reagent.
- Acetaldehyde gives only a light pink colour.
(ii) Acetaldehyde and Acetone
Test: Iodoform Test
- Acetaldehyde (CH CHO) gives a yellow precipitate of iodoform (CHI ).
- Acetone (CH COCH ) also gives the iodoform test but formaldehyde does not.
Step 3: Observation.
Formation of yellow precipitate of CHI confirms the presence of a –COCH or –CHOCH group.

Step 1: Definition.
Tollen's reagent is an ammoniacal silver(I) solution containing the (diamminesilver(I)) complex, usually present as .
Step 2: Role.
It oxidizes aldehydes to acids and gets reduced to metallic silver (silver mirror test).
Step 3: Eliminate wrong options.
(B) and (D) are used in Fehling’s/Benedict’s tests; (C) is not the ammoniacal complex.
Step 4: Conclusion.
Therefore, is Tollen’s reagent (A).

Step 1: Understand carbonyl compounds.
Carbonyl compounds include aldehydes and ketones, which have a carbonyl group ( ) as their functional group. The general formula for aldehydes and ketones is , where is the number of carbon atoms.
Step 2: Eliminate the incorrect options.
- Option (A) O: Correct, this is the general formula for carbonyl compounds like aldehydes and ketones. - Option (B) : Incorrect, this is the general formula for alkanes, not carbonyl compounds. - Option (C) : Incorrect, this formula doesn't represent carbonyl compounds. - Option (D) None of these: Incorrect, as option (A) is correct.
Final Answer:

Step 1: Understanding the properties of formaldehyde.
Formaldehyde (CH₂O) is a simple organic compound. At room temperature, it is typically found in the form of a gas, but in a concentrated form (such as in formalin), it exists as a liquid.
Step 2: Room temperature state of formaldehyde.
At standard room temperature (around 25°C), formaldehyde is in a gaseous state, but when dissolved in water or in a concentrated solution, it appears as a liquid (formalin).
Step 3: Apply to the options.
Formaldehyde at room temperature is most commonly a liquid when dissolved in water, which is why option (B) is correct.
Final Answer:

Step 1: Understand the structure of the compound.
The given structure is CH -CH-CH -CH Cl. This structure represents a butane chain with a chlorine atom (Cl) and a methyl group (CH ) attached to it.
Step 2: Identify the functional groups and their positions.
- The chlorine atom is attached to the second carbon in the chain (2-chloro). - The methyl group is attached to the third carbon in the chain (3-methyl). Thus, the IUPAC name is "2-chloro-3-methyl butane".
Step 3: Apply to the options.
The correct IUPAC name is (B) 2-chloro-3-methyl butane.
Final Answer: