Chemistry - Ionic Equilibrium Question with Solution | TestHub

The $\mathrm{pH}$range between$3.1$ (red) and $4.4$(yellow) is the colour-change interval of methyl orange.

Weak base has $\mathrm{pH} > 7$. So, when methyl orange indicator is added the solution turns yellow & if the solution is titrated against strong acid it turns pinkish red at the end point i.e., $\mathrm{pH} <3.1$.