What does below chemistry rebus means?

What can you catch but never throw?

Our product and our sum always give the same answer. Who are we?

I have Rs.50 and I spend it in the way as below.

A doctor and a boy were fishing. The boy was the doctor’s son, but the doctor was not the boy’s father. Who was the doctor?

There is a hypothetical state between the USA and Mexico border 'Tango'.
Here 70 percent of the population have defective eyesight, 75 percent are hard of hearing, 80 percent have Nose trouble and 85 percent suffer from allergies, what percentage (at a minimum) suffer from all four ailments?

Bay of Bengal is in which state?

What goes up but never comes down?

What has many keys but can’t open a single lock?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211