Methyl orange is an indicator that changes color depending on the pH of the solution. Here's what happens in a sodium hydroxide solution:

* Sodium hydroxide (NaOH) is a strong base. This means it creates a highly alkaline (basic) environment with a high pH.

* Methyl orange is red in acidic solutions and yellow in basic solutions.

Therefore, in a solution of sodium hydroxide, methyl orange will turn yellow.