For a standard acid-base indicator , the visual working range where the color transition is fully ob — Ionic Equilibrium Chemistry Question

💡 Solution & Explanation

The human eye needs one form to be 10 times more concentrated than the other. From the indicator equation $pH = pK_{In} + \log([In^-]/[HIn])$, bounding the ratio from 1/10 to 10/1 gives the functional range $pH = pK_{In} \pm 1$.