Phenol red is an indicator that changes color over a range from ph=6.4 to ph=8.0. what is ka of phenol red?

First, we will get the average pH of the two given values:
average pH = (6.4+8) / (2) = 7.2
At this average pH, the concentration of the acid from the phenol red is equal to the concentration of the base.
pH = 7.2
[H+] = 10^(-7.2) = 6.3 * 10^-8

Phenol red has the general formula HA, this gives us:
HA <> H+ + A- 
At pH = 7.2, [H+] = [A-]
Ka = [H+][A-]/ [HA]
Ka = [H+] = 6.3 x 10^-8

Ithink it’s carbon dioxide

Hello! data: p (pressure) = 1.25 atmv (volume) = ? (in l)t (temperature) = 298 kn (number of mols) = 0.900 molesr (gas constant) = 0.082 (atm*l/mol*k)apply the data to the clapeyron equation (ideal gas equation), see: i hope this . =)