Which of the following species are involved in the reaction of phenol with chloroform and alkali to form salicylaldehyde?

For the Reimer-Tiemann reaction, first, we should write the balanced chemical equation to see all the species involved. Phenol + Chloroform + Alkali → Salicylaldehyde + other products \[C_6H_5OH + CHCl_3 + OH^- \rightarrow C_7H_6O_2 + H_2O + 3Cl^-\]

Based on the balanced chemical equation for the Reimer-Tiemann reaction, the species involved are: 1. Phenol (\(C_6H_5OH\)) 2. Chloroform (\(CHCl_3\)) 3. Alkali (Hydroxide ions, \(OH^-\))

The Reimer-Tiemann reaction mechanism involves three major steps: 1. Formation of dichlorocarbene: The hydroxide ions (\(OH^-\)) from the alkali remove a hydrogen from chloroform (\(CHCl_3\)), creating dichlorocarbene (\(CCl_2\)). 2. Formation of an ortho intermediate: The dichlorocarbene then reacts with the phenol molecule by adding to the ortho position (next to the hydroxyl group) of the benzene ring, forming a dichloromethyl intermediate. 3. Hydrolysis: The intermediate undergoes hydrolysis, where water molecules replace the chlorines. This forms salicylaldehyde, as the final product. Hence, phenol, chloroform, and alkali are the key species involved in the Reimer-Tiemann reaction of phenol to form salicylaldehyde.