What does this rebus riddle means ?

What breaks yet never falls, and what falls yet never breaks?

John was working on a Chemical Mixture whose weight comprise 90% liquid and 10% solid. The total weight of the mixture is 20 pounds. After a while, John noticed that some of the liquid evaporated and now the liquid comprises just 50% of the weight.

What is the weight of the chemical mixture now?

Which wheel of car does not rotate when you turn your car right?

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

Can you find out which triangle will have a bigger area among the following?
1. A triangle with sides 300, 400 and 500
2. A triangle with sides 300, 400 and 700

I have a mouth but I don't eat.
I have a bank but have no money.
I have a bed but i dont sleep.
I wave but have no hands.

Who Am I ?

In the below-given picture of a pretty girl, there is something wrong. Can you find out what it is?

Can you decipher the below rebus?

PBLUESAISNUERSES

What kind of band never plays music?