Acids Bases And Salts

The Tollens test is a qualitative test used in organic chemistry to determine the presence of an aldehyde group. It works by oxidizing aldehydes to carboxylic acids while reducing the Tollens' reagent (ammoniacal silver nitrate) to metallic silver, which appears as a silver mirror on the test tube.

Let's analyze each compound:

• Phenylethanal (C₈H₈O) contains an aldehyde group. It can give a positive Tollens test.
• Acetophenone (C₈H₈O) is a ketone, not an aldehyde. Ketones do not give a positive Tollens test.
• Formic acid (HCOOH) is not an aldehyde; it's a carboxylic acid. Even though formic acid has a structure analogous to an aldehyde, it is generally not tested with Tollens' test like typical aldehydes. It is a unique case where the reactivity towards Tollens' may appear positive due to its reductive capabilities but it is categorized separately from typical aldehyde tests.
• Benzene carbaldehyde (C₇H₆O) is another name for benzaldehyde. It is an aromatic aldehyde and gives a positive Tollens test.

From the analysis, the compounds that yield a positive Tollens test are Phenylethanal and Benzene carbaldehyde. Acetophenone, being a ketone, doesn't, and Formic acid's results are not considered typical for aldehyde identification.

Thus, the correct answer is: A, C, and D only

The problem involves evaluating statements regarding chemical compounds and reactions. Let's analyze each statement:

• (A) Diazonium salts of aromatic amines are more stable than those of aliphatic amines due to resonance stabilization, making the statement "A" correct.
• (B) Ethylamine is indeed soluble in water because it can form hydrogen bonds with water. Therefore, this statement is incorrect.
• (C) Gabriel phthalimide synthesis is used to prepare primary amines effectively by preventing issues like over-alkylation. Thus, statement "C" is correct.
• (D) Aniline's NH₂ group has a +R effect, making it less reactive in Friedel-Crafts acylation because it forms a complex with the Lewis acid catalyst, meaning statement "D" is correct.

Combining this analysis, the correct statements are (A), (C), and (D). Therefore, the answer is: (A), (C) and (D) only

1. Formation of Diazonium Salt: An aryl amine is converted into a diazonium salt via reaction with nitrous acid at low temperatures.
2. Substitution Reaction: In the presence of copper powder and a halogen acid, the diazonium group (N₂⁺) is replaced by a halogen atom (such as Cl or Br).
3. Formation of Haloarene: The major product formed is an aryl halide, commonly termed as haloarene.

• Phenol Structure: Picric acid is derived from phenol, which consists of a benzene ring bonded to a hydroxyl group (-OH).
• Nitro Groups: In picric acid, three nitro groups (-NO₂) are attached to the benzene ring. Their positions are at carbon atoms 2, 4, and 6.
• Naming Convention: According to IUPAC nomenclature, when naming aromatic compounds with substituents, the hydroxyl group takes priority as the principal functional group. Therefore, the name starts with "phenol." The positions of the nitro groups are indicated by numbering the carbons in the benzene ring, starting from the carbon with the hydroxyl group (numbered as 1). As a result, we describe the compound as "2,4,6-Trinitrophenol."

Aspirin is a commonly used medication primarily recognized for its pain-relieving, anti-inflammatory, and antipyretic properties. Chemically, it is known as Acetyl Salicylic acid. The structure of Aspirin consists of a salicylate moiety with an acetyl group attached to it, which differentiates it from other forms of salicylic acid derivatives.

Here is a brief explanation of each term:

• Salicylic Acid: This is the base compound, known for its role in making aspirin, containing a hydroxyl group on a benzene ring.
• Ethyl Salicylic Acid: A hypothetical derivative where the hydroxyl group in salicylic acid might be replaced by an ethoxy group. It does not represent aspirin.
• Methyl Salicylic Acid: Another hypothetical derivative where the hydroxyl group might be substituted by a methoxy group. It is not the same as aspirin.
• Acetyl Salicylic Acid: The correct form, where an acetyl group is linked to the hydroxyl group of salicylic acid to form aspirin.

Aspirin, or Acetyl Salicylic acid, is most recognized by its IUPAC name due to this essential acetyl group substitution.

The order of increasing pKa values of the given compounds reflects their acidity. A lower pKa value indicates a stronger acid. Let's analyze each compound:

1. CH₃COOH (Acetic acid): A common weak carboxylic acid.
2. CH₂OCH₂COOH (Glycolic acid): The presence of an ether group can increase electron donation, slightly weakening the acid.
3. Cl₃COOH (Trichloroacetic acid): Chlorine atoms are electron-withdrawing, enhancing acidity by stabilizing the conjugate base.
4. (CH₃)₃CCOOH (Trimethylacetic acid): The bulky tert-butyl group is electron donating, reducing acidity compared to simpler carboxylic acids.

Based on these considerations, we deduce that the order from lowest to highest pKa value (increasing order of acidity) is: CH₃COOH < CH₂OCH₂COOH < Cl₃COOH < (CH₃)₃CCOOH.

Thus, the correct answer is A < B < C < D.

Aspirin, a widely used drug, is chemically known as Acetyl Salicylic acid. It is an acetylated form of salicylic acid, where an acetyl group (CH₃CO) is attached to the phenolic hydroxyl group of salicylic acid. The chemical formula for Acetyl Salicylic acid is C₉H₈O₄. This modification enhances its therapeutic efficacy and reduces gastrointestinal side effects commonly associated with salicylic acid. Understanding the chemical composition of aspirin helps in comprehending its function and usage in medical applications, primarily as an anti-inflammatory and analgesic agent.

Thus, the correct answer is Acetyl Salicylic acid.

To determine which compound is not an artificial sweetener, we must first understand what each compound mentioned does:

Aspartame: A low-calorie artificial sweetener used in many sugar-free products, noted for its sweet taste.

Alitame: Another low-calorie artificial sweetener, known for being sweeter than aspartame and used in various food items.

Sucralose: A zero-calorie artificial sweetener, made from sugar, often used in drinks and food products.

Sodium benzoate: This compound is primarily used as a food preservative, not a sweetener. It helps prevent the growth of bacteria and fungus.

Based on these descriptions, sodium benzoate is the compound that is not an artificial sweetener. It is a preservative, separating it from the other compounds that are used for sweetening purposes.