A substance (X) is added to the lime solution and then mixed with red cabbage solution. The resultant solution turns out violet in color. What will be the nature of substance (X)?

The correct answer is: X is acid

In the case of red cabbage the color roughly changes as follows;

• pH ≈ 2: red/bright pink, lime juice (which we sprinkled on top of our salad) will cause the pH to sink down this low and make the cabbage red
• pH ≈ 4: light purple
• pH ≈ 6: violet, this is approximately the color of ‘native’ red cabbage.
• pH ≈ 8: blue
• At an even higher pH value, the red cabbage can even turn green/yellowish.
• X is acid