分析化学测试题

ⅠSingle choice ( 2 points per question, 30%)

(一) 1. When 0.20mol•L -1 NaOH standard solution was used to titrate the mixtures of 0.10 mol•L -1H 2SO 4 and

0.10mol•L -1H 3PO 4, ________end points could be observed on the titration curves. （ ）

A. 1

B. 2

C. 3

D. 4

2. Which one of the following is a pair of conjugate acid and base? ( )

A. H 2CO 3—CO 32-

B. HPO 42-—PO 43-

C. H 3PO 4—HPO 42-

D. NH 3-NH 3.H 2O

3. The solubility of Ag 2S in pure water is________(K SPAg2S =2.0×10-48)( )

B. 34sp K

C. 32sp

K D. 34sp

K

4. Which of the following could be used as the primary standard?( )

A. KMnO 4

B.（NH 4）2CO 3

C. HCl

D. K 2Cr 2O 7

5. The equilibrium constant for the reaction of MnO 4- and Fe 2+ is ______

(E 0 (MnO4-/Mn2+)= 1.51 V; E 0 (Fe3+/Fe2+)=0.77V ) ( )

A. 320 B 3.4⨯1012 C 5.2 ⨯1062 D 4.8⨯1063

6. ε of a absorbing complex is always dependent upon the______( C )

A. the stability of the complex

B. the thickness of the container

C. the wavelength of the electromagnetic radiation

D. the concentration of the comples

7. A solution containing commercial cyt c is buffered to pH 7.40 using 85 mmol/L phosphate buffer. If the

solution is diluted with water by a factor of three, what is the resulting pH of the solution? ( D )

A. 2.47

B. 5.15

C. pH > 14

D. nothing happens - pH remains same

8. The %T of a certain solution at a certain wavelength in a 1.0 cm cell is 50%. The absorbance of this same

solution in a 2.0 cm cell is: ( )

a) unknown. We can't calculate it with the information given.

b) 0.15 c) 0.30 d) 0.60

9. What is the ratio of acid to salt in a solution that is pH 7.20 and contains H 3PO 4 and Na 3PO 4 (pKa 1~pKa 3

of H 3PO 4 are 2.12、7.20、12.4 respectively) ( ) a) 1:2 b) 2:3 c) 1:1 d) 2:1

10. A series of solutions containing NaOH, Na 2CO 3, and NaHCO 3 alone or in compatible combination, was

titrated with HCl. The volume of HCl needed to titrate the solution to a phenolphthalein end point is

V 1mL. Continuing to titrate the solution to a bromocresol green end point needed V 2 mL. If 2V 1=V 2,

the component of the mixture is _____________ ( )

A 、NaOH+Na 2CO 3

B 、Na 2CO 3+NaHCO 3

C 、NaOH+NaHCO 3

D 、NaOH+Na 2CO 3+NaHCO 3

11. Which of the following statements is true? ( )

A Precise values may be inaccurate

B Determinate errors can be constant or proportional

C The variance is the square of the standard deviation

D All of the above