CHEM2411 TT2 Rapid Fire

A phosphate solution is at pH = 10. What is the major phosphate specie in solution?

For H₃PO₄: pKa₁ = 2.15; pKa₂ = 7.20; pKa₃ = 12.35

• H₃PO₄

• H₂PO₄^-

• HPO₄^2-

• PO₄^3-

Is a solution of Na₂HPO₄ acidic, basic, or neutral?

For H3PO4: Ka₁ = 7.11 × 10^-3 ; Ka₂ = 6.32 × 10^-8 ; Ka₃ = 4.50 × 10^-13

• Acidic

• Basic

• Neutral

For the titration of 40 mL 0.1M triprotic acid, H₃A with 0.1M of NaOH. What volume of NaOH should be added to the acid solution to reach the 3rd equivalence point?

• 40 mL NaOH

• 20 mL NaOH

• 120 mL NaOH

• 80 mL NaOH

A buffer was prepared by mixing 5.0 mL of 0.10 M NaH₂PO₄ with 2.5 mL of 0.10 M HCl. What is the acid and conjugate base that makes up this buffer?

• Acid: H₃PO₄

  Conj. Base: H₂PO₄^-

• Acid: H₂PO₄^-

  Conj. Base: HPO₄^2-

• Acid: HPO₄^2-

  Conj. Base: PO₄^3-

Which of the following compound is the most soluble in water?

• CuBr

  (K_sp = 5.0 × 10^-9)

• CuCl

  (K_sp = 1.9 × 10^-7)

• CuI

  (K_sp = 1.0 × 10^-12)

• CuSCN

  (K_sp = 4.0 × 10^_-14)

Which of the following compound is equally soluble in acidic solution as it is in pure water?

• HgS

• Ca₃(PO₄)₂

• Al(OH)₃

• AgCl