What does below chemistry rebus means?

In the four images below, can you find the odd one out?

What can run but never walk, have a mouth that never speaks, have a head that never weeps, and have a bed but never sleeps?

Different lights make me strange by changing me into different sizes. What am I?

In a mathematical quiz, you are asked the following question:

Use three 9s in a mathematical expression without dividing or multiplying to form the number one.

Can you answer the question?

A girl says this to her best friend: “I was born in 1955, and I celebrated my 17th birthday last weekend.” Her best friend thinks she’s lying, but she’s actually correct. How is that possible?

Three people are in a room. Ronni looks at the Nile. The Nile looks at Senthil. Ronni is married but Senthil is not married. At any point, is a married person looking at an unmarried person? Yes, No or Cannot be determined.

With the help clues provided in the image, can you find the 5 digit key?

A cat had three kittens: Snophy, Topsy and Jorden. What was the mother's name?

Can you count the number of triangles in the picture below?