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Unit 1: Preparation of Buffers - Practice Quiz

BTY301 — Biochemistry Laboratory 60 Questions
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1 What is the molarity of a solution containing 1 mole of solute in 1 liter of solution?

Buffer preparation with concept of molarity and normality Easy
A. 0.1 M
B. 100 M
C. 10 M
D. 1 M

2 Which formula is used to calculate molarity?

Buffer preparation with concept of molarity and normality Easy
A.
B.
C.
D.

3 What is a buffer solution?

Buffer preparation with concept of molarity and normality Easy
A. A solution that resists changes in pH
B. A solution that always has a pH of 7
C. A solution that rapidly changes pH
D. A solution containing only distilled water

4 A buffer commonly contains which combination of substances?

Buffer preparation with concept of molarity and normality Easy
A. A strong acid and strong base
B. A weak acid and its conjugate base
C. Only a neutral salt
D. Only distilled water

5 Which glassware is commonly used to prepare a solution to an accurate final volume?

Buffer preparation with concept of molarity and normality Easy
A. Volumetric flask
B. Watch glass
C. Beaker
D. Test tube

6 What does the unit represent?

Buffer preparation with concept of molarity and normality Easy
A. Moles per liter
B. Molecules per gram
C. Milligrams per liter
D. Milliliters per mole

7 How many moles are present in of a solution?

Buffer preparation with concept of molarity and normality Easy
A. 1.0 mol
B. 0.5 mol
C. 2.5 mol
D. 0.25 mol

8 What is the first step when preparing a buffer from a solid chemical?

Buffer preparation with concept of molarity and normality Easy
A. Adjust the pH immediately
B. Measure the required mass
C. Add the final volume of water
D. Label the bottle before weighing

9 In buffer preparation, why is the pH measured after the components are mixed?

Buffer preparation with concept of molarity and normality Easy
A. To calculate the molecular mass
B. To confirm the desired acidity or alkalinity
C. To measure the flask volume
D. To determine the solution color

10 What is normality defined as?

Buffer preparation with concept of molarity and normality Easy
A. Liters per mole of solute
B. Moles per liter of solvent
C. Equivalent weights per liter of solution
D. Grams per milliliter of solvent

11 What is the symbol commonly used for normality?

Buffer preparation with concept of molarity and normality Easy
A.
B.
C.
D.

12 For an acid that provides one hydrogen ion per molecule, how are molarity and normality related?

Buffer preparation with concept of molarity and normality Easy
A.
B.
C.
D.

13 What is the normality of a solution of a diprotic acid that donates two hydrogen ions?

Buffer preparation with concept of molarity and normality Easy
A.
B.
C.
D.

14 Which equation is used to dilute a stock solution?

Buffer preparation with concept of molarity and normality Easy
A.
B.
C.
D.

15 What usually happens to the concentration when water is added to a solution?

Buffer preparation with concept of molarity and normality Easy
A. It changes into a solid
B. It increases
C. It decreases
D. It remains exactly doubled

16 A solution contains how many moles in ?

Buffer preparation with concept of molarity and normality Easy
A. 0.05 mol
B. 0.5 mol
C. 1.5 mol
D. 5.0 mol

17 Which measurement is essential when preparing a buffer of a specified molarity?

Buffer preparation with concept of molarity and normality Easy
A. Color of solute and room temperature
B. Shape of the flask and solution odor
C. Label size and stirring speed
D. Mass of solute and final volume

18 A buffer has its best capacity when the concentrations of the weak acid and conjugate base are approximately:

Buffer preparation with concept of molarity and normality Easy
A. Unrelated
B. Both zero
C. Equal
D. Always ten times different

19 Which instrument is commonly used to measure the pH of a buffer accurately?

Buffer preparation with concept of molarity and normality Easy
A. Measuring cylinder
B. Thermometer
C. pH meter
D. Balance

20 If mole of solute is dissolved to make of solution, what is the molarity?

Buffer preparation with concept of molarity and normality Easy
A.
B.
C.
D.

21 What mass of NaCl () is required to prepare of a solution?

Buffer preparation with concept of molarity and normality Medium
A. 5.84 g
B. 3.66 g
C. 1.46 g
D. 2.92 g

22 What volume of HCl is needed to prepare of HCl?

Buffer preparation with concept of molarity and normality Medium
A. 10 mL
B. 25 mL
C. 50 mL
D. 40 mL

23 What is the normality of a sulfuric acid solution when both acidic protons react completely?

Buffer preparation with concept of molarity and normality Medium
A. 0.25 N
B. 0.50 N
C. 2.00 N
D. 1.00 N

24 What mass of NaOH () is required to prepare of a solution?

Buffer preparation with concept of molarity and normality Medium
A. 4.00 g
B. 1.00 g
C. 8.00 g
D. 2.00 g

25 How much of a phosphate stock solution is required to prepare of a phosphate solution?

Buffer preparation with concept of molarity and normality Medium
A. 50 mL
B. 10 mL
C. 5 mL
D. 20 mL

26 A buffer contains equal concentrations of acetic acid and acetate ion. If the of acetic acid is , what is the approximate buffer pH?

Buffer preparation with concept of molarity and normality Medium
A. 3.76
B. 5.76
C. 4.76
D. 4.26

27 A buffer is diluted tenfold with water while the acid-to-conjugate-base ratio remains constant. What is the expected effect on its pH?

Buffer preparation with concept of molarity and normality Medium
A. It decreases by one unit
B. It remains approximately unchanged
C. It increases by one unit
D. It becomes exactly neutral

28 What is the normality of calcium hydroxide, , in an acid–base reaction?

Buffer preparation with concept of molarity and normality Medium
A. 0.125 N
B. 0.500 N
C. 1.000 N
D. 0.250 N

29 When phosphoric acid is completely neutralized by a strong base, what equivalent weight should be used for with ?

Buffer preparation with concept of molarity and normality Medium
A. 98.0 g/eq
B. 49.0 g/eq
C. 32.7 g/eq
D. 16.3 g/eq

30 What mass of anhydrous sodium carbonate () is required to prepare of a solution for complete acid neutralization?

Buffer preparation with concept of molarity and normality Medium
A. 21.2 g
B. 5.30 g
C. 2.65 g
D. 10.6 g

31 Equal volumes of NaCl and NaCl are mixed. What is the final NaCl molarity, assuming additive volumes?

Buffer preparation with concept of molarity and normality Medium
A. 0.05 M
B. 0.10 M
C. 0.30 M
D. 0.15 M

32 What volume of a stock solution is needed to prepare of a solution?

Buffer preparation with concept of molarity and normality Medium
A. 5.0 mL
B. 20.0 mL
C. 10.0 mL
D. 2.5 mL

33 A buffer is prepared by mixing of acetic acid with of sodium acetate. What is the approximate pH if ?

Buffer preparation with concept of molarity and normality Medium
A. 4.26
B. 5.26
C. 4.76
D. 3.76

34 For hydrochloric acid, which relationship is correct when the reaction involves one mole of per mole of HCl?

Buffer preparation with concept of molarity and normality Medium
A.
B.
C.
D.

35 What volume of stock solution is needed to prepare of a solution?

Buffer preparation with concept of molarity and normality Medium
A. 25 mL
B. 20 mL
C. 5 mL
D. 10 mL

36 What mass of sulfuric acid is theoretically required to prepare of solution for complete neutralization? Use .

Buffer preparation with concept of molarity and normality Medium
A. 19.6 g
B. 4.90 g
C. 9.80 g
D. 2.45 g

37 Two acetate buffers have the same acetate-to-acetic-acid ratio, but one has twice the total concentration. Which statement is correct?

Buffer preparation with concept of molarity and normality Medium
A. Both have identical capacity
B. The dilute buffer has greater capacity
C. Capacity depends only on the pH
D. The concentrated buffer has greater capacity

38 What mass of glucose () is required to prepare of a solution?

Buffer preparation with concept of molarity and normality Medium
A. 9.00 g
B. 2.25 g
C. 4.50 g
D. 18.0 g

39 A solution is diluted from to a final volume of . What is the final molarity?

Buffer preparation with concept of molarity and normality Medium
A. 0.025 M
B. 0.080 M
C. 0.050 M
D. 0.800 M

40 A laboratory protocol requires of NaOH. What amount of NaOH, in equivalents, is needed?

Buffer preparation with concept of molarity and normality Medium
A. 0.020 eq
B. 0.200 eq
C. 2.00 eq
D. 0.002 eq

41 A buffer contains acetic acid and acetate ion. Given , what is its approximate pH, assuming ideal behavior?

Buffer preparation with concept of molarity and normality Hard
A.
B.
C.
D.

42 What masses of anhydrous and are required to prepare of a phosphate buffer at ? Use molar masses of and , respectively, and .

Buffer preparation with concept of molarity and normality Hard
A. and
B. and
C. and
D. and

43 What is the normality of when it undergoes complete neutralization by a strong base?

Buffer preparation with concept of molarity and normality Hard
A.
B.
C.
D.

44 What volume of concentrated sulfuric acid, labeled with density , is required to prepare of for complete neutralization?

Buffer preparation with concept of molarity and normality Hard
A.
B.
C.
D.

45 Equal-temperature solutions of of acetic acid and of sodium acetate are mixed. If , what is the approximate pH after mixing?

Buffer preparation with concept of molarity and normality Hard
A.
B.
C.
D.

46 A buffer initially contains each of and . After adding of strong HCl, what is the pH change if ?

Buffer preparation with concept of molarity and normality Hard
A. The pH decreases by units
B. The pH decreases by units
C. The pH increases by units
D. The pH remains exactly unchanged

47 In acidic solution, permanganate is reduced according to . What is the normality of a solution under these conditions?

Buffer preparation with concept of molarity and normality Hard
A.
B.
C.
D.

48 What volume of a stock solution is required to prepare of a solution?

Buffer preparation with concept of molarity and normality Hard
A.
B.
C.
D.

49 What is the normality of when it is titrated to complete neutralization of carbonate by a strong acid?

Buffer preparation with concept of molarity and normality Hard
A.
B.
C.
D.

50 A ammonia buffer is required at . Given , which preparation using stock solutions gives of the buffer before final dilution?

Buffer preparation with concept of molarity and normality Hard
A. each of and
B. ammonia and ammonium chloride
C. ammonia and ammonium chloride
D. each of and

51 A mixture contains of and of . Assuming complete reaction and ideal behavior, what is the final pH?

Buffer preparation with concept of molarity and normality Hard
A.
B.
C.
D.

52 To prepare of acetate buffer from acetic acid and NaOH, which procedure produces equal final concentrations of acetic acid and acetate?

Buffer preparation with concept of molarity and normality Hard
A. Mix acid with base, then dilute
B. Mix acid with base
C. Mix acid with base, then dilute
D. Mix acid with base, then dilute

53 What volume of sulfuric acid is needed to prepare of sulfuric acid?

Buffer preparation with concept of molarity and normality Hard
A.
B.
C.
D.

54 What mass of is needed to provide of phosphate salt? Its molar mass is .

Buffer preparation with concept of molarity and normality Hard
A.
B.
C.
D.

55 A phosphate mixture contains of and of . Given , what is the approximate pH?

Buffer preparation with concept of molarity and normality Hard
A.
B.
C.
D.

56 What is the normality of when the titration endpoint corresponds only to the first proton neutralization?

Buffer preparation with concept of molarity and normality Hard
A.
B.
C.
D.

57 A laboratory must prepare of approximately NaOH using pellets that are NaOH by mass. What mass of pellets should be weighed?

Buffer preparation with concept of molarity and normality Hard
A.
B.
C.
D.

58 Two buffers have the same pH and the same , but buffer X contains each of and , while buffer Y contains each. Which statement is correct?

Buffer preparation with concept of molarity and normality Hard
A. X has tenfold greater acid capacity
B. Y has tenfold greater acid capacity
C. Both have identical acid capacity
D. Capacity depends only on the pH value

59 A solution is prepared by mixing of with of . What is the residual acid normality after reaction?

Buffer preparation with concept of molarity and normality Hard
A.
B.
C.
D.

60 Using acetic acid and sodium acetate, what volumes are needed to prepare of a acetate buffer at ?

Buffer preparation with concept of molarity and normality Hard
A. of each stock
B. of each stock
C. of each stock
D. of each stock
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Unit 2