What does this simple rebus mean?

I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

John and Jacob are twin brothers. One of them is a liar whereas the other one is a truth-teller.

I called their home number and one of them picked up.
I asked. 'Does John lie?' The person replied with a yes.

Whom did I talk with, John or Jacob?

A very interesting trivia question for all.

Why do men's shirts have their buttons on the right side and women's have buttons on the left-hand side?

What is the end of everything?

There once were seven dwarfs who were all brothers. They were all born two years apart. The youngest dwarf is seven years old. How old is his oldest brother?

Find the next number in the series

12, 20, 40, 72, 116, 172 ?

What number does the below three word/phrase identify and why?
1. Deck
2. Year
3. Singing in the Rain

Can you divide numbers from 1 to 9 (1 2 3 4 5 6 7 8 9) into two groups so that the sum of the numbers of each group is equal?

Note: 9 cannot be turned over to make it 6.

How many times can you subtract the number 5 from 25?