Question

When you buy me I am black,
When you use me I am red ,
And whwn you throw me I am white.
Who am I ?

Answer 1

Answer:

litmus paper

Explanation:

I think it is right

Answer 2

Answer:

Hey buddy your answer is charcoal.

Explanation:it is black in colour, when we burn it, it becomes red and after complete burning it becomes white.

Thank you.