What does below chemistry rebus means?

What is more useful when it is broken?

What brings you down but never up?

What came first, the chicken or the egg?

What Time Should the last watch show in the below figure?

A rubber ball keeps on bouncing back to 2/3 of the height from which it is dropped. Can you calculate the fraction of its original height that the ball will bounce after it is dropped and it has bounced four times without any hindrance ?

Can you find a five letter word that is left with only two letters if one is removed?

At a Society election for president, precisely 963 votes were cast.
There is a total of 4 candidates that participate in the election.

The winning candidate exceeds the opponents by 53, 79 and 105 votes.

How many votes do each candidate gets?

I start and end with 500 and carry a 5 in my heart. But I require the first letter and the first number to be complete. I am the name of a King.

Who am I ?

Which Travels Faster? Solve below famous picture riddle: