What is the color of methyl orange
in a basic medium? A) Blue, B) red, C) pink slash
purple, D) colorless, or E) yellow?
Methyl orange is an example of a pH
indicator, a chemical that changes color depending on the pH. This is one of the structures of
methyl orange. You don’t need to worry about the
details of this. I just thought it would be
interesting. When the pH of the surrounding
solution is greater than 4.4, methyl orange is yellow and has this structure. And this is the structure of methyl
orange when the pH drops below 3.1. So, we have a yellow form for
methyl orange and a red form.
Now, let’s look back at the
question. The question asks, what is the
color of methyl orange in a basic medium? We think of a basic medium as
anything with a pH greater than seven. An example of this would be a
solution of sodium hydroxide. A pH greater than seven is
definitely greater than a pH of 4.4, so we would expect methyl orange in a basic
medium to be yellow.
Methyl orange changes color at
about the midpoint of the pH scale that’s dedicated to acids. So, it’s often used in acid
titrations. You can remember the colors it
turns by remembering that red and yellow mix together to make orange. So, our final answer for what is
the color of methyl orange in a basic medium is yellow.