What does below chemistry rebus means?

What is the below Rebus indicate?

You can take four of the five letters out of this word, but the pronunciation never changes. What is the word?

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

How many letters are in the alphabet?

Prove that twice of ten is the same as twice of eleven.

Can you find out the remainder when 3^300 is divided by 5?

Considering the below equation:

V + II - VI = 10
IV - X + VIII = 20
IV - VII + VI = 30

Then, I + II + III = ?

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?

A man was convicted of a minor offence in Akbar court. Akbar decided to give him a chance. He asked him to give a statement. If the statement is true, he will be killed by lions and if it is false, he will be killed by trampling of wild elephants.

The convicted person requested help from Birbal and since the crime was not a big one, Birbal decided to help him. Whatever Birbal suggested impressed Kabir and he let the convicted person go.

What did Birbal suggest to the person?