[ubcdumbass]

Methyl red acid form would have the molecular weight of 269.30g/mol
I can't find information on its base form, but I'm assuming since the equation for methyl red is
[HIn] + [H20] = [H30+] + [In]
Its base form has one less H therefore as each H has a molar mass of ~1g/mol I subtracted one from the molecular weight of the acid form, giving 268.30g/mol

Is this kind of logic correct or am I completely on the wrong track?

Thank you!

[Borek]

Check wikipedia.