Question

How's explain the methil orange ?

Answer 1

`"Methyl orange"` is a large organic molecule...a weak acid in fact...

Explanation:

..whose acidic and basic forms have different and distinct colours....and thus it is used as an acid-base indicator.

And so it is RED at low pH, i.e. as the acid, and yellow in basic media. The colour change occurs at approx. `pH=3.5`...