If you say my name, I will no longer exist. What am I?

How can you take 2 from 5 and leave 4?

In an interview, a boy was asked an unusual question 'How two persons sitting with a table in between them can't see each other?' He was unable to reply. Can you?

A man calls his dog from the opposite side of a river. The dog crosses the river without a bridge or a boat and manages to not get wet. How is this possible?

What does the following BrainBat signifies?

ABCDEFGHIJKLMNOPQRSTUVWYZ

QQQQQQQQQQQQQQQQQQQQQQQQQ.

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?

How can you write nineteen in a manner that if we take out one, it becomes twenty?

I get hot but I never sweat,
I cook food but I am not a chef,
I have a door but you can't enter me,
I have a light but I am not a lamp.
Who am I?

You throw me out when you want to use me and you take me in when you don't want to use me.

Who Am I?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see?