200
A dye that will change colour in acids and alkalis is an _________.
______ paper is used as an indicator in science.
A substance that is neither an acid or alkali and has a PH of 7 is _______.
An _______ is a medicine containing an alkali used to neutralise some of the acid in the stomach to treat heartburn.
A ______________ reaction is when an acid and an alkali cancel each other out.