What will happen if few drop of dilute (hcl) are added to red cabbage juice
Answers
The color of hibiscus tea depends on the pH. It contains anthocyanins, the same pigment that is found in red cabbage and a lot of other red-colored plant parts. At low pH the tea will be red while it is green to blue at higher values. Hibiscus tea, itself, is acidic (and hence, red in color). If you add acid you will not observe a color change (other than what might be expected due to dilution). Adding base, however, will cause the color to change to green/blue. Now, add acid and the color will revert to red.
BTW, anthocyanins have the general structure shown below:
The ‘R’ groups determine which anthocyanin and these groups will be some mix of R = H-, HO- or CH3O- (e.g., cyanidin: R3, R5, R7, R3′& R4′ = HO-, R6 & R5′ = H-, cyanidin is found in grapes and berries such as blackberry, blueberry… and is red with pH<3, violet at pH = 7–8, and blue with pH>11
