What does below chemistry rebus means?

A network of 20 x 10 squares is given to you.

Can you calculate how many unique squares and rectangles can be formed combining two or more individual squares ?

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 ?

A Doctor always sneezes before the rain. Doctor sneezes, Will it rain?

Why is a river so rich ?

What work can one never finish?

Solve the rebus riddle in the picture below.

A journalist was investigating a sacred cult in the jungles of Africa when he was caught by one of the person. He was confined in a cave till the leader arrived. The leader told him that he need to tell him a statement. If he thinks the statement is true, then the journalist head will be chopped off. If he thinks that the statement is false, his head will be smashed with a hammer.

What statement did the journalist make to survive?

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

Spot the cat in the picture below