Identify the correct statement about detergents.

(I) Cationic detergents have germicidal properties and are expensive.

(II) Liquid dishwashing detergents are non-ionic type.

(III) Anionic detergents are also used in toothpastes.

The correct answer is I, II and III.

Key Points

• Cationic detergents have germicidal properties due to their positively charged active groups that disrupt microbial cell membranes; however, they are expensive.
• Liquid dishwashing detergents are generally of the non-ionic type, which helps in reducing surface tension and improving cleaning efficiency without forming excess foam.
• Anionic detergents, which contain negatively charged surfactants, are commonly used in cleaning products such as toothpastes for effective removal of dirt and debris.
• Detergents are broadly classified into anionic, cationic, non-ionic, and zwitterionic types based on the nature of their surfactant groups.

Additional Information

• Anionic detergents contain sulfate or sulfonate groups, making them effective in cleaning oily stains and widely used in household products such as laundry detergents and toothpastes.
• Cationic detergents are quaternary ammonium compounds that are often used in disinfectants and fabric softeners due to their germicidal and antistatic properties.
• Non-ionic detergents lack charged groups in their molecules, making them suitable for applications where low foaming and mild cleaning action are required, such as in dishwashing liquids.
• Zwitterionic detergents contain both positive and negative charges in their molecular structure, making them highly versatile for applications requiring gentle cleaning, such as in skin-care products.
• Detergents are amphiphilic compounds, meaning they possess both hydrophilic (water-attracting) and hydrophobic (water-repelling) properties, enabling them to emulsify oils and fats for effective cleaning.