Question

1. For calculating the pH of 0.01010 M KH PO., which of the following strategies is correct? A. Treat as monoprotic acid system and use Kai B. Treat as monoprotic acid system and use Kaz C. Treat as amphiprotic system and use Ka, and Kaz D. Treat as amphiprotic system and use Kaz and Kaz 2. A 0.100 M NaOH solution is used for titrating an 0.0750 M acetic acid solution (pKa-4.76). What is the pH of the solution when 1/2 Ve of NaOH is added (Ve is the volume of NaOH to be added to reach equivalence point)? A. 6.61 B. 4.76 C.3.28 D. 3.06 3. Which of the following statements of EDTA titration is correct? A. EDTA forms 1:2 complexes with most metal ions B. When the pH is higher, the fraction of fully deprotonated EDTA is larger C. Before the equivalence point of an EDTA titration, the concentration of the free metal is negligible D. At the equivalence point of an EDTA titration, the concentration of the free metal is equal to the concentration of fully deprotonated EDTA 4. Which of the following statements of spectrophotometry is correct? A. Absorbance is linearly proportional to molar absorptivity, solution concentration, and path length B. The energy of a molecule decreases when it absorbs a photon C. Absorbance is the percentage of light that is being absorbed by the solution D. Absorbance is proportional to transmittance 5. The lowest excited state of a sodium atom lies 3.371 x 10 J/atom above the ground state. The degeneracy of the excited state is 2, whereas that of the ground state is 1. What is the fraction of Na in the excited state in an acetylene-air flame at 2600 K? Ng N. 8. k= 1.381 x 10-2 J/K A. 1.67 x 102 B. 1.67 x 10% C. 1.67 x 109 D. 1.67 x 10+