Question

When you pick a particular flower and immerse it in a pH 7 solution there is no change in the color, If you place the same flower in a pH 9 solution, the color changes. Why does this happen?

A. A variation in pH changes the pK_a value of the compound responsible for the color causing it to fluoresce.

B. A variation in pH causes a change in the optical transmission of certain colors allowing the color to be viewed.

C.

A variation in pH causes a change in the structure of the compound responsible for the color.

Answer 1

In this question PH 7 is neutral neithernacidic nor basic if you increase the PH 7 to PH 9 it value changes to basic medium means color changes to blue or approximately blue pka value also increases where in basic solution on increasing PH

Optical transmission of doesn't allow to be view because it goes to darker from transparent to light blue or dark blue depends on flower compound

Variation in PH also change the structure to hydrolyse some groups present in flower to become a basic.