Question

Which halogen is a grey crystalline solid, which turns into violet fumes on heating?​

Answer 1

Answer:

Iodine is a grey solid and produces violet while heating

Answer 2

The halogen which is a grey crystalline soild and turns into violet fumes when heating is Iodine.

Explanation:

• The elements belonging to group 17 are called as Halogens, which literally means salt, hence they are also called as Salt Family.
• The first element of the group is Flourine which is also the smallest and is a gas at room temperature, whereas Iodine has the largest side among the halogen family and is solid at room temperature, and appears as a blue black solid.
• The colour of the fume of the halogen depends on its excitation energy which in turns depends on the size of the element.
• For example, flourine is the smallest element among the family and requires high excitation energy and appears as pale yellow on heating.
• Whereas in case of Iodine which has the largest size in the family, has low excitation energy, hence on heating absorbs yellow light and hence appears dark violet on heating.