Question

Consider the acid/base equilibrium of bromocresol purple shown in the image above. Why is the basic form of bromocresol purple violet, whereas the acidic form is yellow?

Question 6 options:

A) The basic form has more p-orbitals overlapping to form pi molecular orbitals and thus has larger conjugation than the acidic form. The more p-orbitals that participate in a conjugated system, the higher the energy of light absorbed. Hence the basic form absorbs shorter wavelengths of electromagnetic radiation than the acidic form and the basic form reflects longer wavelengths of electromagnetic radiation.

B) The basic form has more p-orbitals overlapping to form pi molecular orbitals and thus has larger conjugation than the acidic form. The more p-orbitals that participate in a conjugated system, the lower the energy of light absorbed. Hence the basic form absorbs longer wavelengths of electromagnetic radiation than the acidic form and the basic form reflects shorter wavelengths of electromagnetic radiation

. C) The basic form has less p-orbitals overlapping to form pi molecular orbitals and thus has smaller conjugation than the acidic form. The more p-orbitals that participate in a conjugated system, the higher the energy of light absorbed. Hence the basic form absorbs shorter wavelengths of electromagnetic radiation than the acidic form and the basic form reflects longer wavelengths of electromagnetic radiation.

D) The basic form has less p-orbitals overlapping to form pi molecular orbitals and thus has smaller conjugation than the acidic form. The more p-orbitals that participate in a conjugated system, the greater the energy of light absorbed. Hence the basic form absorbs longer wavelengths of electromagnetic radiation than the acidic form and the basic form reflects shorter wavelengths of electromagnetic radiation.

Answer 1