What does below chemistry rebus means?

Take one out and scratch my head, I am now black but once was red. What am I?

What is the end of everything?

Find the Goldfish below the given Image.

Solve the riddle below:

If a Chicken says, 'All chickens are liars" is the chicken telling the truth?

You walk into a room where there are three primates held in their respective cages:
1) A lion who is eating the flesh of a goat.
2) An orangutan who is playing with blocks.
3) A donkey who is sitting idle.

Who is the most intelligent primate in the room?

John is looking at Jenifer, but Jenifer is looking at Jacob. John is married, but Jacob is not.

Is a married person looking at an unmarried person ?

Katniss and Peeta are liars. They both lie on some specific days.

Katniss lies on Fridays, Saturdays and Sundays. She speaks the truth on all other days.

Peeta lies on Tuesdays, Wednesdays and Thursdays. He speaks the truth on all other days.

Can you tell that one day of the week when both of them will say "Tomorrow, I will lie."?

How do you go from 98 to 720 using just one letter?

I am an odd number. Take away a letter and I become even. What number am I?