'S' refers to the number of seconds in a day and 'H' refers to the number of hours in ten years. Which quantity out of these two is greater?

In the Chess Board picture below white army is arranged. You need to add a black army on the board such that no piece is under any threat.
Note: Army comprised of 1 king, 1 queen, 2 rooks, 2 bishops, 2 knights, and 8 pawns.

What does below pictogram mean?

Make eight squares by moving only two matchsticks.
Note- Square can be of different sizes.

Move four matchsticks to the below square to form three squares?

You’ll find me on Mercury, Earth, Mars, Jupiter, Saturn, and Uranus. But never Neptune, or Venus. What am I?

What's the only room from which no one can enter or leave

I can be cracked, made, told, and played. What am I?

Cristina was born in 1888. She just had her 30th birthday today how did that happen?

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