_________ solution of phenol in water acts as a disinfectant.

1 %

The correct answer is option 1. 1 %.

Phenol is a well-known antiseptic and disinfectant. It has been used historically in medical settings and industrial applications due to its ability to kill or inhibit the growth of microorganisms.

Effective Concentration

Concentration:

1% Phenol Solution: This concentration is effective in disinfecting surfaces and skin. Phenol at 1% concentration is strong enough to inactivate bacteria, fungi, and some viruses.

Mechanism of Action

Phenol acts as a disinfectant through the following mechanisms:

Protein Denaturation: Phenol disrupts the proteins and enzymes within microorganisms. By denaturing the proteins, phenol effectively destroys the structural integrity of the microbial cells and prevents their replication.

Cell Membrane Disruption: Phenol can also damage the cell membranes of microorganisms, leading to leakage of cellular contents and cell death.

Lipid Solubility: Phenol is lipophilic (fat-loving) and can dissolve in lipids. This property allows it to penetrate cell membranes and exert its toxic effects internally.

Application and Use

Historical Use: Phenol was one of the first antiseptics used in medical procedures. Although it has been largely replaced by other disinfectants due to its toxicity and potential for causing skin irritation, it is still used in some applications.

Current Use: In modern contexts, phenol is used in disinfectant formulations and some antiseptic products. A 1% solution is considered effective for general disinfection purposes due to its sufficient antimicrobial action.

Safety Considerations

While effective, phenol is toxic and can cause skin irritation or more severe effects if not handled properly. Therefore, while a 1% solution is effective for disinfection, precautions must be taken to avoid direct contact and ensure proper ventilation during use.

Summary:

A 1% phenol solution is effective as a disinfectant because it provides the right balance of antimicrobial activity while being manageable in terms of safety and handling. It acts primarily through protein denaturation and cell membrane disruption. This concentration ensures that phenol is potent enough to serve as a disinfectant while remaining practical for use in various applications.