Which number should replace the question mark?

When I go in I might cause pain. I cause you to spit and ask you not to swallow. I can fill your hole. What am I?

What's the next in the series?

H, Be, F, S, Mn, Kr, In, Gd, Tl, ?

You can see it everyday, But cannot touch it at will. What is it?

12345 a famous South Indian actor
567 is a path in jumbled form
8 & 10 are same letters
9 is one among the first six alphabets.
WHO AM I?

There are seven sisters in a house in a village where there is no electricity or any gadget.

Sister-1: Reading Novel
Sister-2: Cooking
Sister-3: Playing Chess
Sister-4: Playing Sudoku
Sister-5: Washing clothes
Sister-6: Gardening

what is Sister-7 doing ?

They are three errirs in this question. Can you find them?

A finger goes in me. You fiddle with me when you're bored. The best man always has me first. What am I?

There are four 3-link chains. All you have to do is join them into a big 12-link chain. For joining two closed links, one of the links must be cut and placed onto the other link for closing.

How many minimum links will you have to cut to make the big chain?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?