The only metal that is anti-bacterial is?

Analysis

The question asks for the specific metal among the given options that possesses anti-bacterial (or oligodynamic) properties. This means the metal has the ability to kill or inhibit the growth of microorganisms like bacteria, viruses, and fungi.

Concept Explanation

The phenomenon where metal ions (especially heavy metals) exhibit a toxic effect on living cells, including bacteria, is known as the oligodynamic effect.

While several metals (like silver and gold) are well-known for this, among the options provided, Copper is scientifically recognized for its potent antimicrobial properties. When bacteria come into contact with a copper surface, the copper ions disrupt the bacterial cell membrane, create oxidative stress, and damage the DNA of the bacteria, effectively killing them. This is why copper is frequently used in hospitals for surfaces like door handles and bed rails to reduce the spread of infections.

Step-by-Step Solution

1. Evaluate Iron (A): Iron is essential for biological processes (like oxygen transport in hemoglobin) but does not possess significant intrinsic anti-bacterial properties.
2. Evaluate Sodium (B): Sodium is a highly reactive alkali metal. It reacts violently with water and is not used for its anti-bacterial properties.
3. Evaluate Aluminium (C): Aluminium is widely used for its lightweight and corrosion-resistant properties, but it is not classified as an anti-bacterial metal.
4. Evaluate Copper (D): Copper is widely documented in chemistry and microbiology for its oligodynamic effect, making it the correct choice for an anti-bacterial metal.

Conclusion

Based on the chemical properties of the metals listed, Copper is the only one that acts as an effective anti-bacterial agent.

Exam Tip

When you see questions about "anti-bacterial" or "antimicrobial" metals in your Chemistry or Biology exams, always look for Copper (Cu) or Silver (Ag). These are the two most common answers in Nigerian secondary school examinations regarding this specific property.