Step 1: Identifying the reaction.
The reaction involves the condensation of acetic acid (CH3COOH) with ammonia (NH3) under heat (\( \Delta \)). This is a type of amide formation reaction.
Step 2: Explanation of the products.
- (1) CH2=CHO: This is the structure for an aldehyde, not related to the amide formation in the given reaction.
- (2) CH3CH==NOH: This represents an imine, which is not the correct product of the reaction.
- (3) HCONH--CH3: This is methylamide (acetamide), which is the correct product of the reaction between acetic acid and ammonia.
- (4) All of these: This is incorrect since only acetamide is the correct product.
Step 3: Conclusion.
The correct answer is (3) HCONH--CH3.