7 Most VSAQ’s of Organic Chemistry Chapter in Inter 2nd Year Chemistry (TS/AP)

Table of Contents

2 Marks

VSAQ-1 : What are ambident nucleophiles?

Ambident nucleophiles are molecules or ions with two potential donor atoms, such as the cyanide ion (CN^-) and the nitrite ion (NO2^-). These compounds play a significant role in chemistry by providing versatility in chemical reactions due to their ability to donate electron pairs through different atoms.

VSAQ-2 : What are Enantiomers?

Enantiomers are a pair of non-superimposable mirror image molecules. Examples include d-lactic acid and l-lactic acid. They have the same chemical formula but differ in their three-dimensional arrangement, which can lead to distinct biological effects, making them important in fields like pharmacology and biochemistry.

VSAQ-3 : How is aniline prepared?

Aniline is prepared through a chemical reaction involving nitrobenzene, hydrogen gas (H₂), and a catalyst, usually palladium (Pd). The reaction can be represented as follows:

C₆H₅NO₂ + 3H₂ → Pd C₆H₅NH₂ + 2H₂O

VSAQ-4 : How is Grignard reagent prepared?

Grignard reagents are synthesized through a reaction involving alkyl or aryl halides and magnesium (Mg) in anhydrous (dry) ether. The reaction can be summarized as follows:

Rx + Mg →┴ (dry ether) RMgX

VSAQ-5 : Explain Carbylamine reaction with one example.

The Carbylamine reaction, also known as the Isocyanide test, is used to identify primary amines. In this test, a primary amine reacts with chloroform (CHCl3) and alcoholic potassium hydroxide (KOH) to form an isocyanide compound, characterized by its foul odor.

Example:

For instance, when methylamine (CH3NH2) undergoes the Carbylamine reaction, it produces an isocyanide:

CH₃NH₂ + CHCl₃ + KOH → CH₃NC (Isocyanide) + 3H₂O + KCl

VSAQ-6 : Compare the acidic strength of acedic acid, Chloroacetic acid, benzoic acid and phenol.

Among acetic acid, chloroacetic acid, benzoic acid, and phenol:

Chloroacetic acid is the strongest acid due to the electron-withdrawing effect of chlorine, resulting in a lower pKa value.
Benzoic acid is moderately acidic, with a pKa value between acetic acid and chloroacetic acid.
Acetic acid is a weak acid with a higher pKa than chloroacetic acid and benzoic acid.
Phenol is the weakest acid among them, with the highest pKa value.

VSAQ-7 : Write the reaction showing α-halogenation of carboxylic acid and give its name.

The α-halogenation of carboxylic acids, known as the Hell-Volhard-Zelinsky (HVZ) reaction, involves treating a carboxylic acid (RCOOH) with chlorine or bromine (X2) in the presence of red phosphorus (P) as a catalyst. This reaction results in the formation of α-halo carboxylic acids (RCOX) and hydrogen halide byproducts (HX).