Question

Alcohols, Phenols and Ethers
Alcohols and phenols are formed when a hydrogen atom in a hydrocarbon, aliphatic and aromatic respectively, is replaced by -OH group. These classes of compounds find wide applications in industry as well as in day-to-day life. For instance, have you ever noticed that ordinary spirit used for polishing wooden furniture is chiefly a compound containing hydroxyl group, ethanol. The sugar we eat, the cotton used for fabrics, the paper we use for writing, are all made up of compounds containing -OH groups. The common name of an alcohol is derived from the common name of the alkyl group and adding the word alcohol to it. For example, \(\mathrm{CH_3OH}\) is methyl alcohol. The simplest hydroxy derivative of benzene is phenol. It is its common name and also an accepted IUPAC name. As structure of phenol involves a benzene ring, in its substituted compounds the terms ortho (1,2-disubstituted), meta (1,3-disubstituted) and para (1,4-disubstituted) are often used in the common names.
In ethers, the four electron pairs, i.e., the two bond pairs and two lone pairs of electrons on oxygen are arranged approximately in a tetrahedral arrangement. The bond angle is slightly greater than the tetrahedral angle due to the repulsive interaction between the two bulky (-R) groups.

The catalyst involved in the production of methanol through hydrogenation of carbon monoxide is

• A. ZnO-Cr\(_2\)O\(_3\)
• B. ZnO/Pt
• C. Anhyd.AlCl\(_3\)
• D. Anhyd.FeCl\(_3\)

Hint:

Industrial methanol from CO and H2 uses a zinc oxide and chromium oxide catalyst.

Answer 1

The Correct Option is A

Step 1: Sort the catalysts by use:
Anhydrous AlCl3 and FeCl3 are Lewis acids. Chemists use them to make electrophiles in aromatic substitution. Hydrogenation of CO is not that type of reaction. This removes options 3 and 4.

Step 2: Think about the industrial process:
Methanol is made by passing CO and H2 over a catalyst at high pressure. The catalyst must be a stable oxide that works at high temperature.

Step 3: Pick the right oxide:
The textbook process uses ZnO-Cr2O3 (a zinc oxide and chromium oxide mixture). Platinum with ZnO is not the standard choice.

Step 4: Conclude:
Option 1 is the catalyst for the reaction $CO + 2H_2 \to CH_3OH$.

Final Answer:
Hydrogenation of CO to methanol uses the ZnO-Cr2O3 catalyst.\[ \boxed{\mathrm{ZnO\text{-}Cr_2O_3}} \]