What does below chemistry rebus means?

What's the only room from which no one can enter or leave

A girl is twice as old as her brother and half as old as her father. In 50 years, her brother will be half as old as his father. How old is the daughter now?

By moving exactly three matchsticks can you make the below equation true.It can be solved by 3 ways.

In The 1st month of this year(the year 2013), I noticed that the date 13-1-13 (13 January 2013) is special.

This date is special as:

Date * Month = Year.

Can you figure out which year of this century has a maximum number of such dates?

Spelt forwards I’m what you do every day, spelled backwards I’m something you hate. What am I?

There is an ancient kingdom where every married woman keeps information regarding the fidelity of other men. However, what they don't know is the fidelity of their own husbands. Also, there is an ancient belief that they don't tell each other about the fidelity of their husbands.

On a certain day, the queen of the kingdom declares that she has identified at least one unfaithful man in the kingdom. She allows the wives to identify and gives them authority to kill their husbands if they are unfaithful at midnight.

How will the wives manage it?

Three friends named Mr. Black, Mr. Yellow and Mr. Green enter a pub on a weekend night. They are wearing either a Black, Yellow or Green shirt.

Mr. Yellow says to them, 'Did you notice that we all are wearing different color shirts than our names?'

To this, the man who was wearing the Green shirt said. 'Wow, thats right.'

Can you identify who is wearing which colour shirt ?

What 5-letter word typed in all capital letters can be read the same upside down?

If eleven plus two equals one, what does nine plus five equal?