Chapter 3, Problem 118EQ

You wish to add enough NaOCl (sodium hypochlorite) to a 150 m³ swimming pool to provide a dose of 5.0 mg/L TOTOCI as Cl2. (a) How much NaOCI (kg) should you add? (Note: the equivalent weight of NaOCl is based on the reaction: NaOCl + 2H + 2 e→CI + Na +H₂O.) (10 pts) (atomic weight: Na 23, O 16, C1 35.5) (b) The pH in the pool after the NaOCl addition is 8.67. To improve disinfection, you want at least 90% of the TOTOCI to be in the form of HOCI (pKa 7.53). Assuming that HOCI/OCI is the only weak acid/base group in solution, what volume (L) of 10 N HCl must be added to achieve the goal? (15 pts) Note that part a) is a bonus question for undergraduate students. If you decide not to work on this part of the question, you many assume TOTOCI = 7×10-5 M for part b).

Part A 2K(s)+Cl2(g)+2KCI(s) Express your answer in grams to three significant figures. Part B 2K(s)+Br2(1)→2KBr(s) Express your answer in grams to three significant figures. Part C 4Cr(s)+302(g)+2Cr2O3(s) Express your answer in grams to three significant figures. Part D 2Sr(s)+O2(g) 2SrO(s) Express your answer in grams to three significant figures. Thank you!

A solution contains 10-28 M TOTCO3 and is at pH 8.1. How much HCI (moles per liter of solution) is required to titrate the solution to pH 7.0? (H2CO3: pKa1=6.35, pKa2=10.33)