Ultimate Organic Chemistry Quiz

Explanation
The boiling point of solutions is not solely determined by the vapor pressure equaling the external pressure. The boiling point of a solution is actually higher than the boiling point of the pure solvent due to the presence of solute particles, which disrupt the intermolecular forces and require more energy to break the bonds and convert into vapor. Therefore, the statement is false.

Explanation
Vacuum distillation is used to separate heat-sensitive or thermolabile liquid compounds at reduced pressure (below atmospheric pressure), not at 1atm. By lowering the pressure, the boiling point of the compounds decreases, allowing for separation without decomposition. Therefore, the given statement is false.

Explanation
Chloral hydrate is not more stable than chloral, therefore it is not used in the synthesis of iso nitroso acetanilide.

Explanation
Acetone can be tested by the iodoform test because it contains a methyl ketone group. The iodoform test is used to detect the presence of methyl ketones, such as acetone, by reacting them with iodine and a base. This reaction produces a yellow precipitate of iodoform, which confirms the presence of acetone. Therefore, the given statement is true.

Explanation
When a more volatile solute is added to a pure liquid, it decreases the boiling point (BP) of the liquid. This is because the solute molecules disrupt the attractive forces between the liquid molecules, making it easier for the liquid to vaporize and reach its boiling point. As a result, the BP of the pure liquid decreases.

Explanation
Electron-withdrawing groups in the para position do not decrease the acidity and nucleophilicity of phenol. In fact, these groups increase the acidity of phenol by stabilizing the negative charge on the oxygen atom. Additionally, electron-withdrawing groups also enhance the nucleophilicity of phenol by making the oxygen atom more electron-deficient. Therefore, the given statement is false.

Explanation
The reaction between Toluidine, CCl3CH(OH)2, and NH2OH.HCl produces 2-hydroxyimino-N-Phenylacetamide.

Explanation
Chloral hydrate is a compound that contains a hydroxyl group (-OH) attached to the chloral molecule. This hydroxyl group can form two hydrogen bonds with other molecules or functional groups. On the other hand, chloral does not have a hydroxyl group and therefore cannot form hydrogen bonds. Hence, the statement that chloral hydrate can form two hydrogen bonds while chloral cannot is true.

Explanation
The Vigreux column is a type of fractionating column that is designed to improve the separation of compounds with a small boiling point difference. It consists of a series of indentations or "baffles" along the length of the column, which increases the surface area available for vaporization and condensation. This increased surface area allows for more efficient separation of compounds with a boiling point difference of 30-40°C. Therefore, the statement that the Vigreux column allows reasonable separation of compounds with a boiling point difference of 30-40°C is true.

Explanation
O-nitrophenol and p-nitrophenol cannot be separated by fractional distillation using Hempel column because they have very similar boiling points and would not form distinct fractions during the distillation process. Alternative separation techniques such as chromatography or solvent extraction would be more suitable for separating these compounds.

Explanation
Steam distillation is a technique used to separate volatile compounds from non-volatile substances. In this process, steam is passed through the mixture, causing the volatile compounds to vaporize. The vapor is then condensed and collected, resulting in the separation of the desired compound. The splash head is a crucial component in steam distillation as it helps in controlling the flow of steam and preventing any splashing or loss of the mixture. Therefore, the splash head is specifically designed for steam distillation, making it the correct answer.

Explanation
The statement is false because the oxidation of phenols by a strong oxidizing agent does not produce carboxylic acids. Instead, it produces quinones. Carboxylic acids are typically formed when alcohols are oxidized, not phenols.

Explanation
Acetone can be tested by iodoform because when acetone reacts with iodine and sodium hydroxide, it forms a yellow precipitate of iodoform. This reaction is a characteristic test for the presence of acetone. Therefore, the statement "Acetone can be tested by iodoform" is true.

Explanation
The theoretical yield can be calculated by first determining the number of moles of A, B, and AB using their respective volumes and densities. Then, using the molar mass of AB, the number of moles of AB can be converted to grams. The theoretical yield is the mass of AB obtained from the reaction. In this case, the theoretical yield is 27.03 grams.

Explanation
In the synthesis of p-iodobenzoic acid from p-aminobenzoic acid, cooling in an ice bath is necessary because arene diazonium salts are very weak compounds. These salts are highly unstable and can easily decompose at higher temperatures. By cooling the reaction mixture in an ice bath, it helps to control the temperature and prevent the decomposition of the diazonium salt, allowing it to react with iodide ions to form p-iodobenzoic acid.