Q4. At 20°C, hydroxyl ion (OH) concentration of a solution is 10-5.5 M. The pH of that solution is 6.5 8.5 7.5 5.5

1. Water is frequently disinfected with chlorine gas, forming hypochlorous acid (HOCI), which partially ionizes to hypochlorite (OCI) and hydrogen ions as follows: HOCI H+ + OCI- The concentration of HOCI, which is the desired disinfectant, depends on the water pH. a) Write the equations to express the two ionization fractions for HOCI, that is, ao and ai. b) Plot ionization fractions vs pH, clearly identifying a regions and pKa, at 25 °C. c) Plot speciation of HOCI vs pH (log[OCI] vs pH) for a Croci-= 0.05, clearly identifying regions and pKa, at 25 °C.

Small droplets of carbon tetrachloride at 68 °F are formed with a spray nozzle. If the average diameter of the droplets is 300 μm what is the difference in pressure between the inside and outside of the droplets? Pa

5-18. The solubility product of calcium fluoride (CaF2) is 3.45 x 10-" at 25°C. Will a fluoride concentration of 1.0 mg/L be soluble in a water containing 200 mg/L of calcium?