What does below chemistry rebus means?

Which Number is the odd one out?

A) 7145
B) 2716
C) 5321
D) 4135

What is the end of everything?

If your uncle’s sister is not your aunt, what relation is she to you?

Akbar called Birbal and asked him to draw a line on the floor. He asked Birbal to make that line smaller without erasing it. Birbal smiled and did it before Akbar could blink his eyes.

How did he managed to do it?

In the given picture, in how many ways can you read the word "Tiger"?

Why is it very easy to weigh a fish?

Eight of us go fourth, not back, to protect our king from an attack. What are we?

One day, John and his friends were playing around. Jacob hit something with a Pin and it popped. John's dad came into the room that very moment, but he wasn't mad. In fact, he was smiling. What did Jacob hit?

A fresher was sitting in an interview. The interviewer said, "This is the last question of your interview. Tell me the accurate position of the centre of this table where your resume is kept."

How can he answer this question? What will you have answered to such a question?