Which of the following are not chemical changes 1. Tempering of iron 2. Conversion of the iron piece into an electro-magnet by passing the current around the iron 3. Melting of iron 4. Rusting of iron Select the correct answer using the code given below:?

Option 3 : 1, 2 and 3

The correct answer is Option 1.

• Melting of iron metal, Bending of iron rod, tempering of iron, and drawing a wire of iron metal - are examples of Physical Changes of Iron. Hence option 1 is incorrect.
• Rusting of iron is an example of chemical change.
• The reaction of Iron is

                                             Fe + O2 + H2O > Rust

• The magnetization of iron occurs due to the temporary alignment of the electrons present in it in one direction only. This is done by rubbing the north pole of the magnet in the middle of the magnet towards its end. This is a physical change.

1. Physical Change

• Properties such as shape, size, state of the substance, and its color are known as physical properties. Change in these properties is known as Physical Change.

1. ​Chemical Change

• A change in which one or more new substances are formed is known as chemical change.