Replace the question mark with the correct number in the below-given picture?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

My first is in chocolate but not in ham. My second is in cake and also in jam. My third at tea time is easily found. Altogether, this is a friend who is often around. What is it?

I know there are two methods by using three time the same number with a plus(+) operator , you can make sum as 60.

One of them is 20+20+20.

whats the other way ?

I have a five and a three-gallon jar. Assuming there is an infinite supply of water, how can I measure one-gallon water?

You have two buckets of 11 liters and 6 litres.
How can you measure exactly 8 litres?

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

What have one eye but still cannot see?

John can eat 27 chocolates in an hour, Jacob can eat 2 chocolates in 10 minutes, and Jolly can eat 7 chocolates in 20 minutes. How long will it take them to share and eat a box of 120 chocolates whilst playing Chess?

Living above a star, I do not burn
Eleven friends and they do not turn
I can just be visited in a sequence, not once or repeatedly
PQRS are my initials
Can you tell my name accurately?