As a technician in a large pharmaceutical research firm, you need to produce 400. mL of 1.00 M potassium phosphate buffer solution of pH = 7.05. The pKa of H2PO4− is 7.21.You have the following supplies: 2.00 L of 1.00 M KH2PO4 stock solution, 1.50 L of 1.00 M K2HPO4 stock solution, and a carboy of pure distilled H2O.How much 1.00 M KH2PO4 will you need to make this solution?

50 mL sample solution containing Na2CO3 and NaOH is titrated with 0.2 M HCl solution. In the presence of phenolphthalein indicator, the acid consumption is 15 mL. Then, the titration is continued by adding bromocresol green indicator, and in the presence of this indicator, the acid consumption is 10 mL. Accordingly, which of the following is the amount of Na2CO3 (in grams) in the sample? (NaOH: 40 g / mol; NazCO3: 106 g / mol)

A 1 litre solution is made by adding 0.6646 moles NaH2PO4 and 0.8868 moles Na2HPO4. What will be the final pH of the solution after the addition of 9.3137ml of 4.5994 molar HCL? The pKa of sodium dihydrogen phosphate is 6.86

Potassium cyanide is a toxic substance, and the median lethal dose depends on the mass of the person or animal that ingests it. The median lethal dose of KCNKCN for a person weighing 215 lblb (97.5 kgkg ) is 8.84×10−3 molmol . What volume of a 0.0250 MM  KCN KCN solution contains 8.84×10−3 molmol of KCNKCN? ------ Gastric acid pH can range from 1 to 4, and most of the acid is HClHCl. For a sample of stomach acid that is 4.42×10−3 MM in HClHCl, how many moles of HClHCl are in 10.5 mLmL of the stomach acid? Express the amount to three significant figures and include the appropriate units.

When making 500.0 mL of a buffer solution at pH 4.00 from 0.100 M NaCHO2 and 0.200 M HCHO2, what volume of each solution should be used to obtain a solution with the maximum buffering capacity at this pH? The Ka of HCHO2 is 1.8 x 104 A. 0.39 L NaCHO2 and 0.11 L HCHO2 B. 0.33 L NaCHO2 and 0.17 L HCHO2 C. 0.39 L NaCHO2 and 0.11 L HCHO2 D. 0.44 L NaCHO2 and 0.060 L HCHO2

Human blood contains one buffer system based on phos-phate species and one on carbonate species. Assuming that blood has a normal pH of 7.4, what are the principal phosphateand carbonate species present? What is the ratio of the two phosphate species? (In the presence of the dissolved ions andother species in blood, Kₐ₁of H₃PO4=1.3X10⁻², Kaₐ₂=2.3X10⁻⁷, and Kₐ₃=6X10⁻¹²; Kₐ₁ of H₂CO₃=8X10⁻⁷ and Kₐ₂=1.6X10⁻¹⁰.)

Consider a buffer solution that contains 0.40 M C6H4(CO2H)2 and 0.25 M C6H4(CO2H)(CO2K). pKa(C6H4(CO2H)2)=2.95. Calculate its: a)pH, the change in pH if 0.160 g of solid NaOH is added to 200 mL of this solution. b)If the acceptable buffer range of the solution is ±0.10 pH units, calculate how many moles of H3O+ can be neutralized by 250 mL of the initial buffer.

Shown below is the titration curve for phosphoric acid. What is the composition of a solution of phosphoric acid at pH 2.1? a) 100% H3PO4 b) 50% H3PO4 and 50% H2PO4-  c) 100% H2PO4- d) 50% H2PO4- and 50% HPO42-  e) 100% HPO42-  f) 50% PO43- and 50% HPO42- g) 100% PO43-

Lactobacillus bulgaricus is the main bacterium used in the production of yogurt and requires an acidic environment to grow effectively. To prepare an agar solution of this bacterium, a 100.0 mL 0.100 M buffer solution pH 5.00 must be prepared. The only available reagents in the laboratory are solid benzoic acid (HC6H5COO, MM = 122.12), solid sodium bicarbonate (NaHCO3, MM = 84.01), 1.00 M HCl, and 1.00 M NaOH. Acid dissociation constants: Benzoic acid, HC6H5COO: pKa,1 = 4.19 Carbonic acid, H2CO3: pKa,1 = 6.37, pKa,2 = 10.32 Identify the most appropriate conjugate acid-base pair for the target buffer. Determine the amounts of the acidic and basic species in the buffer (in millimoles).

134 grams of potassium sorbate KCH3 (CH)4CO2 is fully dissolved in 100.00 mL of water, which is carefully transferred to a conical flask. Then 100.00 mL of 0.240 M HNO3 is added dropwise to this solution from a burette. Given: Ka (sorbic acid) = 1.7 × 1O^-5 Showing all your calculations and reasoning, determine the pH of the solution that results after the addition of all the acid mentioned above. Suppose that the titration continues. Determine the pH of the solution in the flask at theequivalence point