4. Hypobromous acid (HOBr) is produced in the blood and has properties that combat pathogens. It is also used in bleaches and other cleaning products. The following is a reversible reaction: HOBr → H+ + OBr–
a. Write the equation you would use to calculate the Ka of this reaction.
b. If [H+] at equilibrium is 9.1 × 10–6, what is the Ka of the reaction, given a final HOBr concentration
of 0.33 M?

The content of manganese (mn) in steel was determined spectrophotometrically and with the use of the standard addition method. an unknown sample of mn from a digested steel sample gave an absorbance of 0.185 when analyzed spectrophotometrically. when 5.00 ml of solution containing 95.5 ppm mn was added to 50.0 ml of the unknown steel solution (digested sample), the absorbance was 0.248. calculate the concentration, in parts-per-million (ppm), of mn in the digested steel sample solution.