Definition

1. Noun:
   • Alum: The common name for potassium aluminum sulfate, a double sulfate salt of aluminum and potassium. It is a white, crystalline substance with a sour, astringent taste, traditionally used for a variety of household and industrial purposes.

Usage Examples

• Noun:
  • Người ta thường dùng phèn chua để lọc nước. (People often use alum to purify water.)
  • Phèn chua là một chất cầm màu trong nghề nhuộm vải. (Alum is a mordant in the fabric dyeing trade.)
  • Theo kinh nghiệm dân gian, phèn chua có thể dùng làm thuốc sát trùng nhẹ. (According to folk experience, alum can be used as a mild antiseptic.)

Advanced Usage

• In traditional Vietnamese cuisine, alum is sometimes used in tiny amounts in certain recipes, like in the making of some types of crispy pickles or to improve the texture of some foods.
  • Cho một chút phèn chua vào sẽ giúp dưa muối được giòn. (Adding a little alum will help keep the pickles crisp.)

Variants and Related Words

• Phèn (n): A general term for various sulfate-based salts (alums), including . The context usually specifies the type.
  • Phèn có nhiều loại như phèn chua, phèn đen. (There are many types of alum, such as potassium alum and iron alum.)

Synonyms

• Potassium alum: The specific chemical name.
• Aluminum potassium sulfate: The systematic chemical name.

Related Concepts

• Chất keo tụ (Flocculant): Alum acts as a flocculant in water purification, causing fine particles to clump together so they can be removed.
• Chất cầm màu (Mordant): In dyeing, alum is used as a mordant to fix dyes to fabrics.

1. Alum