Consider the phosphoric acid/dihydrogen phosphate (H_3PO_4/H_2PO_4) buffer system, where the Ka = 7.5e-03 for phosphoric acid.
(a) Give the formula of a salt that you could use to get dihydrogen phosphate ions in solution.
(b) Calculate the pH of the buffer system if 2.00 moles of H_3PO_4 and 1.00 mole H_2PO_4 are present in 1.00 L of solution.
(c) Write the chemical equation showing how the buffer reacts when sodium hydroxide is added to the buffer.
(d) Indicate how the moles of H_3PO_4 are affected by the addition of the sodium hydroxide.
(e) Calculate the new pH if 25.0 mL of 2.0 M sodium hydroxide is added to the buffer solution prepared in part (b).
(f) Calculate the pH if 25.0 mL of 2.0 M sodium hydroxide is added to 1.00 L of pure water.
(g) Compare your answers to parts (e) and (f). Explain the difference.
Consider the phosphoric acid/dihydrogen phosphate (H_3PO_4/H_2PO_4) buffer system, where the Ka = 7.5e-03 for phosphoric acid.
(a) Give the formula of a salt that you could use to get dihydrogen phosphate ions in solution.
(b) Calculate the pH of the buffer system if 2.00 moles of H_3PO_4 and 1.00 mole H_2PO_4 are present in 1.00 L of solution.
(c) Write the chemical equation showing how the buffer reacts when sodium hydroxide is added to the buffer.
(d) Indicate how the moles of H_3PO_4 are affected by the addition of the sodium hydroxide.
(e) Calculate the new pH if 25.0 mL of 2.0 M sodium hydroxide is added to the buffer solution prepared in part (b).
(f) Calculate the pH if 25.0 mL of 2.0 M sodium hydroxide is added to 1.00 L of pure water.
(g) Compare your answers to parts (e) and (f). Explain the difference.