Question

Peeling of Onions causes tears as onion releases:
1. Sulphonic Acid
2. Sulfenic Acid
3. Amino Acid
4. Carbolic Acid

Answer 1

Correct Answer - Option 2 : Sulfenic Acid

The correct answer is Sulfenic Acid.

• The peeling of Onions causes tears as onion releases Sulfenic Acid.
• Onions produce the chemical irritant known as syn-Propanethial-S-oxide.
• It stimulates the eyes' lachrymal glands so they release tears.
• Scientists used to blame the enzyme alliinase for the instability of substances in a cut onion. The synthase enzyme converts the amino acids sulfoxides of the onion into sulfenic acid.

• A sulfenic acid is an organosulfur compound and oxoacid with the general formula RSOH.
• It is the first member of the family of organosulfur oxoacids, which also include sulfinic acids and sulfonic acids, RSO2H and RSO3H, respectively.
• The base member of the sulfenic acid series with R = H is hydrogen thioperoxide. 

Acid	Details
Sulphonic Acid	A sulfonic acid (or sulphonic acid) refers to a member of the class of organosulfur compounds with the general formula R−S(=O)2−OH, where R is an organic alkyl or aryl group and the S(=O)2(OH) group a sulfonyl hydroxide. As a substituent, it is known as a sulfo group.
Amino Acid	Amino acids are organic compounds that contain amino and carboxyl, functional groups, along with a side chain specific to each amino acid. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen, although other elements are found in the side chains of certain amino acids.
Carbolic Acid	Phenol (also called carbolic acid) is an aromatic organic compound with the molecular formula C6H5OH. It is a white crystalline solid that is volatile. The molecule consists of a phenyl group (−C6H5) bonded to a hydroxy group (−OH). Mildly acidic, it requires careful handling because it can cause chemical burns.