Question

Denatured alcohol with colour and foul smell is made now a days by mixing ethanol with

• A. Methanol
• B. $ZnSO_{4}$ and thiophene
• C. $CuSO_{4}$ and pyridine
• D. $FeSO_{4}$ and furan
• E. $Fe_{2}(SO_{4})_{3}$ and hexane

Hint:

Methanol was traditionally used but is highly toxic.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
This is a factual question about the process of denaturing alcohol. Denatured alcohol (or methylated spirits) is ethanol that has been made unfit for human consumption by adding specific substances.
Step 2: Detailed Explanation:
The purpose of denaturing alcohol is to avoid the high taxes levied on alcoholic beverages. The added substances, called denaturants, should make the alcohol poisonous, bad-tasting, foul-smelling, or nauseating. - Historically, methanol was a common denaturant (hence the name "methylated spirits"). Methanol is highly toxic. While still used, other agents are now more common for specific purposes. - To make the denatured alcohol visually identifiable and unpleasant, coloring agents and substances with a strong, foul odor are often added. - Copper sulfate (CuSO\(_4\)) is added to give the alcohol a characteristic blue or greenish color. - Pyridine is a heterocyclic organic compound with a very distinct, strong, and unpleasant fish-like odor. It is also toxic. - The combination of CuSO\(_4\) (for color) and pyridine (for foul smell and toxicity) is a standard method used to denature ethanol. Let's look at the other options: - (A) Methanol is a denaturant, but it is colorless and doesn't provide the color and specific foul smell described. - (B), (D), (E): These contain other salts or organic compounds not typically used for this specific purpose. Thiophene and furan have smells, but pyridine is the classic choice for a foul-smelling denaturant. Step 3: Final Answer:
Denatured alcohol is commonly made by mixing ethanol with CuSO\(_4\) (for color) and pyridine (for foul smell).