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1.) What is the pH of a solution prepared by mixing 100.00 mL of 0.020 M Ca(OH)2 with 50.00 mL of 0.300 M NaOH? Assume that the volumes are additive.
2.) Calculate the pH of a buffer that is 0.145 M HC2H3O2 and 0.202 M KC2H3O2. The Ka for HC2H3O2 is 1.8 × 10-5. Calculate the pH of a buffer that is 0.145 M HC2H3O2 and 0.202 M KC2H3O2. The Ka for HC2H3O2 is 1.8 × 10-5. 4.60 4.74 9.01 4.89 5.05
Expert Answer
Resultant molarity M = M1V1 + M2V2 / M1+M2
M = ((0.02 * 100) + (0.3*50))/(100+50)
M = 0.1133
pOH = -log(OH-)
pOH = -log(0.1133)
pOH = 0.9458
pH = 14 – pOH = 14 – 0.9458 = 13.0542
pH of a buffer solution,
pH = pKa + log([salt]/[acid])
pH = -log(1.8*10^-5) +log(0.202/0.145)
pH = 4.89 for mixed buffer solution.
