Question

Total number of nucleophiles from the following is: \(\text{NH}_3, PhSH, (H_3C_2S)_2, H_2C = CH_2, OH−, H_3O+, (CH_3)_2CO, NCH_3\)

• A. 5
• B. 6
• C. 4
• D. 7

Hint:

A nucleophile is typically an electron-rich species capable of donating electrons. Common examples include amines, thiols, and hydroxide ions.

Answer 1

The Correct Option is A

To determine the total number of nucleophiles among the given species, we need to understand what a nucleophile is. A nucleophile is a chemical species that donates an electron pair to form a chemical bond in relation to a reaction. Nucleophiles are typically negatively charged or neutral with lone pairs of electrons.

Let's evaluate each species:

• \(\text{NH}_3\) (Ammonia): Ammonia is a classic nucleophile due to its lone pair of electrons on the nitrogen atom. Therefore, it is a nucleophile.
• \(PhSH\) (Thiophenol): The sulfur atom in thiophenol contains a lone pair of electrons, making it a good nucleophile.
• \((H_3C_2S)_2\) (Diethyl sulfide): This molecule has sulfur with lone pairs, making it a nucleophile.
• \(H_2C = CH_2\) (Ethene): Ethene is an alkene, which can act as a nucleophile in certain reactions, such as epoxidation, due to the electron density in the \(\pi\) bond.
• \(OH^-\) (Hydroxide ion): Being negatively charged with lone pair electrons, it is a strong nucleophile.
• \(H_3O^+\) (Hydronium ion): This species is not a nucleophile; it is an electrophile, as it is electron-deficient.
• \((CH_3)_2CO\) (Acetone): Acetone is not a nucleophile in typical reactions. It is usually involved as a solvent or an electrophile due to the presence of the carbonyl group.
• \(NCH_3\) (Methyl isocyanide): Generally considered a nucleophile due to lone pairs on nitrogen, but less common.

Counting the nucleophiles: NH\(_3\), PhSH, (H\(_3\)C\(_2\)S)\(_2\), H\(_2\)C = CH\(_2\), and OH\(^-\) are nucleophiles. Thus, there are 5 nucleophiles.

Answer: 5