MCQ Detailed View

Rust stains on clothes are a common problem and are caused by iron oxide (Fe₂O₃). When iron or steel comes into contact with moisture and oxygen, it forms rust. If rust particles get transferred onto fabric, they leave behind reddish-brown stains that are difficult to remove with normal washing.

The most effective way to remove rust stains from cloth is by using an oxalic acid solution. Oxalic acid (H₂C₂O₄) is a mild organic acid that has strong reducing properties. It works by reacting with iron oxide and converting it into a soluble compound that can be washed away easily. This chemical reaction breaks down the stain at the molecular level, which is why oxalic acid is widely used in stain removal and cleaning products.

To apply oxalic acid solution for stain removal, the stained area of the cloth is treated with a small amount of the solution and then rinsed thoroughly with water. It is important to wash the fabric completely after treatment to ensure that no acid remains, as prolonged exposure may weaken the fibers.

The other options in the question are not suitable for rust removal. Alcohol is an organic solvent useful for ink or oil stains but not effective on rust. Kerosene oil can dissolve grease but has no effect on iron oxide stains. “None of these” is incorrect because oxalic acid is the scientifically correct choice.

In chemistry, this example highlights the practical use of acids in daily life. Oxalic acid is also found naturally in certain plants, such as spinach and rhubarb, though in small amounts. However, in cleaning, it is used in carefully prepared solutions for safe and effective results.

Thus, the correct answer is Oxalic Acid Solution, which is the proven chemical treatment for removing rust stains from fabrics.