Boric acid cannot be used in which of the following applications?

Boric acid (H₃BO₃) is a weak, inorganic acid with mild antiseptic, antifungal, and preservative properties. It is widely used in medicine, cosmetics, and industry, but its applications must consider toxicity and concentration.

1. 
   

   As an antiseptic in medicine:
   Boric acid is commonly used in ointments and antiseptic powders for minor cuts and burns. Its mild antiseptic property helps prevent bacterial growth.

   
   


2. 
   

   For washing eyes:
   Very dilute boric acid solutions are used as eye washes to relieve minor irritation, conjunctivitis, or inflammation. Concentration is critical to avoid toxicity.

   
   


3. 
   

   In soda bottles:
   Boric acid cannot be used in soda bottles or any food product. It is toxic when ingested, and even small amounts can cause nausea, vomiting, and other health issues. Therefore, its use in beverages or food containers is strictly prohibited.

   
   


4. 
   

   For enamel and glazes:
   In industry, boric acid is used in ceramic glazes and enamels. It acts as a flux, lowering the melting point of silica and improving surface smoothness. It is safe for this application because it is part of non-edible industrial materials.

   
   

The restriction on boric acid in food-related applications is crucial because oral ingestion can lead to poisoning, whereas topical or industrial uses are safe under controlled conditions.

Thus, among the given options, the correct answer is C) In soda bottles, highlighting the importance of understanding safe and unsafe applications of chemicals in chemistry