Methyl orange is red in a solution. On adding base, its colour becomes yellow. What is the conclusion?

Correct answer: The solution moved from acidity toward less acidic or basic condition

Methyl orange is red in a sufficiently acidic medium and yellow in a neutral or alkaline medium, with a transition range between them. Adding a base consumes some hydrogen ions and shifts the solution away from strong acidity. The yellow colour therefore indicates movement toward a less acidic, neutral, or basic condition. Option A is correct; the observation does not prove that a metal formed or that no chemical change occurred.