Methyl orange used as an indicator in titrations is ______ on the alkaline side and _______ on the acid side.

Methyl orange used as an indicator in titrations is ______ on the alkaline side and _______ on the acid side.

• A. Colorless, Orange
• B. Orange, Red
• C. Reddish-Orange, Reddish-Purple
• D. Yellow, Salmon Pink

Answer: (D)

Methyl orange changes color with pH: it stays yellow in basic solutions and turns red in strongly acidic solutions, with the transition occurring around pH 3.1 to 4.4. In a titration, you want the indicator to be yellow on the alkaline side and red (a reddish color) on the acidic side so the color change brackets the equivalence point. The option that shows yellow for the alkaline side and a reddish-pink/red tone for the acid side aligns with this behavior. While the exact acid-side shade can be described as salmon pink in some depictions, it still reflects the red end of the spectrum seen in acidic conditions. The other color pairings do not match methyl orange’s known color change with pH, so this is the best fit.

Methyl orange changes color with pH: it stays yellow in basic solutions and turns red in strongly acidic solutions, with the transition occurring around pH 3.1 to 4.4. In a titration, you want the indicator to be yellow on the alkaline side and red (a reddish color) on the acidic side so the color change brackets the equivalence point. The option that shows yellow for the alkaline side and a reddish-pink/red tone for the acid side aligns with this behavior. While the exact acid-side shade can be described as salmon pink in some depictions, it still reflects the red end of the spectrum seen in acidic conditions. The other color pairings do not match methyl orange’s known color change with pH, so this is the best fit.