pH Meters and Ion Analysers Flashcards
1
Q
- Which of the following is the formula for pH calculation?
a) log10[H+]
b) -log10[H+]
c) log2[H+]
d) -log2[H+]
A
b) -log10[H+]
2
Q
- Pure water is known to be which of the following?
a) Weak electrolyte
b) Strong electrolyte
c) Neither weak nor strong
d) Not an electrolyte
A
a) Weak electrolyte
3
Q
- Which of the following is the value of hydrogen ion
concentration of pure water?
a) 1×107 moles/litre
b) 1×105 moles/litre
c) 1×106 moles/litre
d) 1×108 moles/litre
A
a) 1×107 moles/litre
4
Q
- Which of the following is the value of hydroxyl ion
concentration of pure water?
a) 1×107 moles/litre
b) 1×105 moles/litre
c) 1×106 moles/litre
d) 1×108 moles/litre
A
a) 1×107 moles/litre
5
Q
- Which of the following is the relation between hydrogen
and hydroxyl ion concentration of pure water?
a) Value of hydrogen ion concentration is greater
b) Value of hydroxyl ion concentration is greater
c) They are both always the same
d) The concentrations keep changing
A
c) They are both always the same
6
Q
- Which of the following is the relation between the
concentration of hydrogen and hydroxyl ions in an acidic
solution?
a) Value of hydrogen ion concentration is greater
b) Value of hydroxyl ion concentration is greater
c) They are both always the same
d) The concentrations keep changing
A
a) Value of hydrogen ion concentration is greater
6
Q
- The Nernst equation is given by which of the following
statements?
a) E=Eo + 2.303 RT/F log CH
b) E=Eo – 2.303 RT/F log CH
c) E=Eo + 2.303 RT×F log CH
d) E=Eo – 2.303 RT×F log CH
A
a) E=Eo + 2.303 RT/F log CH
7
Q
- Which of the following is the relation between the
concentration of hydrogen and hydroxyl ions in a basic
solution?
a) Value of hydrogen ion concentration is greater
b) Value of hydroxyl ion concentration is greater
c) They are both always the same
d) The concentrations keep changing
A
b) Value of hydroxyl ion concentration is greater
8
Q
- Why is Standard hydrogen electrode called as the
primary reference electrode?
a) It has a known output potential
b) It has a constant output potential
c) Its output potential is independent of the composition
of the solution
d) Its output potential is zero volts
A
d) Its output potential is zero volts
9
Q
- The measurement of hydrogen ion concentration can be
made by measuring the potential developed in an
electrochemical cell.
a) True
b) False
A
a) True
10
Q
- Slope factor is independent of temperature.
a) True
b) False
A
b) False
11
Q
- Which of the following is not the characteristic of a
reference electrode?
a) It must have a known output potential
b) It must have a constant output potential
c) Its output potential is dependent on the composition of the solution
d) It is employed in conjunction with the indicator or
working electrode
A
c) Its output potential is dependent on the composition of the solution
12
Q
- Which of the following is the simple and most
convenient hydrogen electrode?
a) Pascal Hydrogen electrode
b) Bourne Hydrogen electrode
c) Hilderbant Hydrogen electrode
d) West Hydrogen electrode
A
c) Hilderbant Hydrogen electrode
13
Q
- Hydrogen electrode which is the reference electrode
can be used as which of the following?
a) Anode only
b) Cathode only
c) Anode or Cathode
d) Salt bridge
A
c) Anode or Cathode
14
Q
- Which of the following is not the disadvantage of
hydrogen electrode?
a) Platinum can be easily poisoned
b) Presence of oxidising agents alters the potential
c) It gives a salt error
d) H2 gas at 1 atmospheric pressure is difficult to set up
and transport
A
c) It gives a salt error
15
Q
- In Hydrogen electrode, the electrode is placed in a
solution of ____ M Hcl. Fill in the blank.
a) 0.5
b) 1
c) 2
d) 3
A
b) 1
16
Q
- If hydrogen electrode acts as cathode, hydrogen is
reduced.
a) True
b) False
A
a) True
17
Q
- The composition of glass membrane in glass electrode
cannot have which of the following?
a) Sodium silicate
b) Calcium silicate
c) Lithium silicate
d) Barium silicate
A
d) Barium silicate
18
Q
- Which of the following is the purpose of added
membranes in the glass membrane of the glass electrode?
a) They act as tightners
b) They act as filters
c) They act as conditioners
d) They act as collectors
A
a) They act as tightners
19
Q
- Which of the following cannot form the inner
reference electrode in glass electrodes?
a) Silver electrode
b) Copper electrode
c) Calomel electrode
d) Silver chloride electrode
A
b) Copper electrode
20
Q
- The pH response of glass electrode is limited entirely
to the area of the special glass membrane bulb.
a) True
b) False
A
a) True
21
Q
- Which of the following is not the advantage of glass
electrodes?
a) It gives accurate results for high as well as low pH values
b) It is simple to operate
c) It has no salt error
d) Modern electrodes can withstand severe treatment
A
a) It gives accurate results for high as well as low pH values
22
Q
- Which of the following is not the disadvantage of glass
electrodes?
a) Poor readings are obtained in buffered or unbuffered solutions
b) The electrode must be washed thoroughly with distilled water to obtain proper results
c) Materials suspended on glass should be wiped out
neatly to obtain proper results
d) It is affected by oxidation reduction potentials in the
solution
A
d) It is affected by oxidation reduction potentials in the
solution
23
Q
- Which of the following cannot be used as secondary
reference electrode?
a) Calomel electrode
b) Silver-silver chloride electrode
c) Mercury-mercury sulphate electrode
d) Glass electrode
A
d) Glass electrode
24
Q
- Which of the following is known as calomel?
a) Silver chloride
b) Mercury chloride
c) Potassium chloride
d) Mercury sulphate
A
b) Mercury chloride
25
Q
- The calomel electrodes are classified based on which of
the following?
a) Materials used in the electrode
b) Amount of mercury present
c) Concentration of Kcl
d) Purity of mercury
A
c) Concentration of Kcl
26
Q
- Which of the following calomel electrodes are used for
accurate work?
a) Saturated calomel electrode
b) Electrode with 0.1M Kcl
c) Electrode with 1M Kcl
d) Electrode with 2M Kcl
A
b) Electrode with 0.1M Kcl
27
Q
- When the calomel electrode acts as the cathode which of the following does not occur?
a) Mercury ions are discharged at the electrode
b) More calomel passes into the solution
c) There is a decrease in the concentration of chloride ions
d) There is an increase in the concentration of chloride
ions
A
d) There is an increase in the concentration of chloride
ions
28
Q
- Calomel electrode can behave as which of the following
components?
a) Anode only
b) Cathode only
c) Anode or cathode
d) Salt bridge
A
c) Anode or cathode
29
Q
- Which of the following is not the characteristics of a
calomel electrode?
a) The potential of electrode is not temperature
dependent
b) Preparation of electrode is easy
c) Value of potential or emf is higher for lower
concentration of Kcl
d) Value of potential decreases with increasing
concentration of Kcl
A
a) The potential of electrode is not temperature
dependent
30
Q
- Which of the following is not the characteristics of
silver/silver chloride electrode?
a) These electrodes have good electrical and chemical
stability
b) It can be used in temperatures greater than 600oC
c) It can be used in places or solutions that have strong
reducing agents
d) It should not be used in solutions that contain proteins,
sulphide or bromide
A
c) It can be used in places or solutions that have strong
reducing agents
30
Q
- While using reference electrodes, the internal liquid
level should always be kept above that of the sample
solution.
a) True
b) False
A
a) True
31
Q
- Which of the following salt bridge solutions must be used for silver/silver chloride electrode?
a) Saturated KCl
b) Saturated K2SO4
c) Saturated LiCl
d) Saturated KNO3
A
a) Saturated KCl
32
Q
- LiCl salt bridge is more suitable in organic solvents than
KCl.
a) True
b) False
A
a) True
33
Q
- Good choice for storing combination electrodes is in a buffer solution having which of the following pH?
a) pH1
b) pH2
c) pH3
d) pH4
A
d) pH4
34
Q
- Which of the following is not the advantage of gel-filled
electrodes?
a) Low maintenance
b) Rugged in construction
c) Easy to maintain
d) Does not cause clogging
A
d) Does not cause clogging
35
Q
- The gel used in combination electrodes does not have which of the following characteristic?
a) Non-toxic
b) USP grade
c) Inorganic material
d) Polyacrylamide
A
c) Inorganic material
36
Q
- Beckman coulter gel filled combination electrodes
provide which of the following features to overcome
various problems that occur in gel filled electrodes?
a) Filters
b) Semi-permeable membrane
c) Gas-permeable membrane
d) Micro-pore junction
A
d) Micro-pore junction
36
Q
- In which of the following solutions must combination electrodes be soaked after cleaning?
a) KCl
b) LiCl
c) KNO3
d) K2SO4
A
a) KCl
37
Q
- Gel filled combination electrodes operate in a wide
temperature range.
a) True
b) False
A
a) True
38
Q
- pH meters can be considered as voltage sources with
which of the following internal resistances?
a) Very low resistance
b) Moderate resistance
c) Very high resistance
d) No resistance
A
c) Very high resistance
38
Q
- The electrodes used in pH measurement have which of
the following internal resistances?
a) Very low resistance
b) Moderate resistance
c) Very high resistance
d) No resistance
A
c) Very high resistance
38
Q
- In combination electrodes, both the electrodes must
be maintained at different temperatures.
a) True
b) False
A
b) False
39
Q
- Which of the following is the simplest of pH meters?
a) Null-detector type pH meter
b) Direct reading type pH meter
c) Digital pH meter
d) Modern pH meter
A
a) Null-detector type pH meter
40
Q
- Which of the following is not a failure in pH meters?
a) Defective electrodes
b) Defective input circuitry
c) Defective electronic circuitry
d) Defective calibration
A
d) Defective calibration
41
Q
- In which of the following ways can zero drift be reduced
in pH meters?
a) Using filter
b) Giving zero adjustment arrangement
c) Keeping the input impedance high
d) Using balanced and differential amplifiers
A
d) Using balanced and differential amplifiers
41
Q
- Which of the following can be used to provide
automatic temperature compensation?
a) Proper insulation
b) Calibration for different temperatures
c) Thermistor
d) Thermometer
A
c) Thermistor
42
Q
- Which of the following is not the characteristic of null
detector type pH meter?
a) It can be battery operated
b) It has less accuracy
c) It is easy to maintain
d) Its electronic circuits are simple
A
b) It has less accuracy
42
Q
- Which of the following is not the characteristic of direct
reading type pH meters?
a) Simple operation
b) Quick to use
c) Continuous indication output
d) It requires balancing process
A
d) It requires balancing process
43
Q
- Which of the following is not the characteristic of
chopper amplifier pH meter?
a) Direct voltage from the electrodes is chopped at the
main frequency
b) Using choppers for high-input resistance gives rise to spikes of waveforms at the output
c) It leads to stability in DC output of phase-sensitive
rectifier
d) Magnitude of surge increases in the glass electrode
output
A
c) It leads to stability in DC output of phase-sensitive
rectifier
44
Q
- In which of the following ways can the disadvantages of chopper amplifier type pH meter be overcome?
a) Using zero corrected DC amplifier
b) Using modern design
c) Using digital design
d) Using vibrating condenser
A
d) Using vibrating condenser
45
Q
- The zero stability of vibrating condenser amplifier type
pH meter is much better than a direct coupled amplifier.
a) True
b) False
A
a) True
46
Q
- In vibrating condenser amplifier type pH meter, to
maintain good performance which of the following has to
be done?
a) Frequency of the vibrator should be stable
b) Frequency of the vibrator should be constant
c) Amplitude of the vibrator should be constant
d) Both frequency and amplitude of the vibrator should be
A
d) Both frequency and amplitude of the vibrator should be
46
Q
- If an instrument fails to balance at zero, it is most likely
that the electrodes are defective.
a) True
b) False
A
b) False
47
Q
- Which of the following is not the characteristic of ion
selective electrodes?
a) It is fragile
b) Easy to use
c) Available in different sizes and shapes
d) It is insensitive to many ions
A
a) It is fragile
48
Q
- In glass membrane electrode, the glass containing 11% Na2O, 18% Al2O3, 71% SiO2 is highly sensitive to which of the following ions?
a) Sodium
b) Hydrogen
c) Nitrogen
d) Chlorine
View Answer
A
a) Sodium
49
Q
- In liquid membrane electrode, the liquid ion exchanger is held in a porous disc of _____________
a) Solid material
b) Semi-permeable membrane
c) Hydrophobic material
d) Water absorbing material
A
c) Hydrophobic material
50
Q
- In recent liquid membrane electrodes, the porous liquid membrane is replaced with which of the following?
a) Polyvinyl chloride
b) Polyacryl chloride
c) Polyester membrane
d) Polyacryl amide
A
a) Polyvinyl chloride
51
Q
- Which of the following is used in potassium electrode in liquid membrane electrodes?
a) Ionomycin
b) Valinomycin
c) Nonactin
d) Gramicidin
A
b) Valinomycin
52
Q
- In solid state membranes, the body of the electrodes are made of which of the following?
a) Polyvinyl chloride
b) Plastic
c) Polythene
d) Teflon
A
d) Teflon
53
Q
- Which of the following is not the characteristic of ion
selective electrodes?
a) Simple to use
b) Inexpensive
c) Narrow concentration range
d) Operates in wide range of temperature
A
c) Narrow concentration range
54
Q
- Which of the following is not a problem of ion selective electrodes?
a) Interference with other ions
b) Output is influences by ionic strength
c) Drift in electrode potential during a sequence of
measurements
d) Can measure only positive ions
A
d) Can measure only positive ions
54
Q
- Ion selective electrode are unaffected by colour or
turbidity of the solution.
a) True
b) False
A
a) True
55
Q
- Which of the following is the effective concentration
measured at the electrode head?
a) Selectivity coefficient
b) Ionic strength
c) Activity
d) Activity coefficient
A
c) Activity
56
Q
- The value of activity coefficient is always in which of
the following ranges?
a) Zero
b) Less than zero
c) Less than 1
d) Greater than 1
A
c) Less than 1
57
Q
- Which of the following specifies the relation between
ionic strength and activity coefficient?
a) Directly proportional
b) Inversely proportional
c) Equal
d) No particular relation
A
b) Inversely proportional
58
Q
- The difference between measured activity and actual concentration becomes higher at higher concentration. Is this statement true or false?
a) True
b) False
A
a) True
59
Q
- In Ammonia electrode, diffusion of dissolved ammonia
occurs through the membrane until which of the following
conditions occur?
a) Concentration becomes equal on both sides
b) Activity becomes equal on both sides
c) Partial pressure becomes equal on both sides
d) Differential pressure is low
A
c) Partial pressure becomes equal on both sides
59
Q
- Ion selective electrodes have ________ linear range
and _________ detection limit than the pH electrode.
a) Lower, lower
b) Lower, higher
c) Higher, lower
d) Higher, higher
A
b) Lower, highe
60
Q
- When electrode potential response is plotted as a
function of ammonia concentration on a semi-log graph,
the graph obtained will be ____________
a) A straight line
b) Parabolic
c) Sigmoidal
d) A curve
A
a) A straight line
61
Q
- In fluoride ion electrode, the potential corresponding to level of the fluoride ion is described by which of the following equations when E is the measured electrode potential, Eo is the reference potential and A is the level of
fluoride ions in solution?
a) E=Eo+0.0591 log A
b) E=Eo-0.0591 log A
c) E=Eo+0.0896 log A
d) E=Eo-0.0896 log A
A
b) E=Eo-0.0591 log A
62
Q
- How can samples above 1M in ammonia concentration be measured using ammonia electrode?
a) It must be diluted and measured
b) It cannot be measured
c) The electrode has to be modified for measuring
d) It can be measured directly
A
a) It must be diluted and measured
63
Q
- The dilution of solution must not reduce the level of
ammonia below _________
a) 10-2 M
b) 10-5 M
c) 10-8 M
d) 10-9 M
A
b) 10-5 M
64
Q
- Which of the following factors does not the
reproducibility of the ammonia electrode?
a) Temperature
b) Drift
c) Noise
d) Dilution
A
d) Dilution
65
Q
- The performance of ammonia electrode is not affected by sample colour and turbidity.
a) True
b) False
A
a) True
66
Q
- What does TISAB which is used to overcome
interferences stand for?
a) Total Isolation Strength Absolute Buffer
b) Total Ionic Strength Absolute Buffer
c) Total Ionic Strength Adjustment Buffer
d) Total Isolation Strength Adjustment Buffer
A
c) Total Ionic Strength Adjustment Buffer
67
Q
- Which of the following causes main interference in
Fluoride electrode?
a) H+ ions
b) OH– ions
c) Li+ ions
d) Cl– ions
A
b) OH– ions
68
Q
- Which of the following gas permeable membrane is
used for ammonia gas sensing electrode?
a) Silicon rubber
b) Microporous Teflon membrane
c) Fluorocarbon
d) Polythene
A
c) Fluorocarbon
68
Q
- Crystal membrane of ion selective electrode can be
regenerated by washing with which of the following?
a) Alcohol
b) Iodine solution
c) Acidic solution
d) Basic solution
A
a) Alcohol
69
Q
- For fluoride electrode, the electrode response curve will not only shift but will change slope with changes in temperature.
a) True
b) False
A
a) True
70
Q
- Which of the following gas permeable membrane is
used for carbon dioxide gas sensing electrode?
a) Silicon rubber
b) PVC membrane
c) Fluorocarbon
d) Polythene
A
a) Silicon rubber
71
Q
- The response time of the biocatalytic membrane
electrode is poor when used with complex organic
molecules.
a) True
b) False
A
b) False
72
Q
- Which of the following reference electrode is placed in the solution of carbon dioxide electrode?
a) Calomel electrode
b) Silver/silver chloride electrode
c) Mercury/mercury sulphate electrode
d) Glass electrode
A
73
Q
- Biocatalytic membrane electrode cannot be used for the
measurement of which of the following gases?
a) Ammonia
b) Carbon dioxide
c) Hydrogen
d) Nitrogen
A
d) Nitrogen
74
Q
- The biocatalytic membrane used in the ammonia
selective electrode is which of the following?
a) Urea
b) Urease
c) Acrylamide
d) Polyacrylamide
A
b) Urease
75
Q
- Which of the following materials are used as a gel to
which biocatalytic membrane is fixed in ammonia selective
electrode?
a) Urea
b) Urease
c) Acrylamide
d) Polyacrylamide
A
c) Acrylamide
76
Q
- If a solid or liquid membrane is placed in pure water, the membrane dissolves slightly, producing an equilibrium concentration of the measured ion. This is represented as
__________
a) A constant, Eo
b) Activity
c) Blank correction, Cb
d) Concentration of standard solution, Cs
A
c) Blank correction, Cb
77
Q
- The biocatalytic membrane is attached to the glass
electrode using which of the following materials?
a) Nylon mesh
b) Teflon
c) Silicon rubber
d) Polythene
A
a) Nylon mesh
78
Q
- The response time of the biocatalytic electrode is a
function of the thickness of the enzyme layer.
a) True
b) False
A
a) True
79
Q
- In carbon dioxide electrode, the membrane separates
which of the following?
a) Sodium carbonate, magnesium chloride
b) Magnesium hydrogen carbonate, sodium chloride
c) Sodium hydrogen carbonate, sodium chloride
d) Magnesium carbonate, magnesium chloride
A
b) Magnesium hydrogen carbonate, sodium chloride
80
Q
- During which of the following conditions is the blank
correction not necessary?
a) If sample concentration rises in linear response region
b) If sample concentration falls in linear response region
c) If sample concentration rises in non-linear response
region
d) If sample concentration falls in non-linear response
region
View Answer
A
b) If sample concentration falls in linear response region
81
Q
- During which of the following conditions is the blank
correction necessary?
a) If sample concentration rises in linear response region
b) If sample concentration falls in linear response region
c) If sample concentration rises in non-linear response
region
d) If sample concentration falls in non-linear response
region
A
d) If sample concentration falls in non-linear response
region
82
Q
- Ion analysers need calibration once in which of the
following durations?
a) Every two or three hours
b) Every nine or ten hours
c) Every 24 hours
d) Every 48 hours
A
a) Every two or three hours
83
Q
- In ion analysers, which of the following serve the dual
purpose of controlling the operating current of FET and
providing current gain?
a) FET itself does it
b) SCR
c) Op-amp
d) Diode
A
c) Op-amp
84
Q
- The presence of dirt or moisture degrades which of the
following?
a) Circuit components
b) High input impedance of buffer amplifier
c) Low input impedance of buffer amplifier
d) Low output impedance of buffer amplifier
A
b) High input impedance of buffer amplifier
85
Q
- Which of the following is not a type of ground in ion
analyser?
a) Chassis and electrostatic ground
b) Digital ground
c) Analog ground
d) Reference ground
A
d) Reference ground
86
Q
- The timing for a microprocessor and for all signals is
generated by the CPU clock.
a) True
b) False
A
a) True
87
Q
- Which of the following is the only operator entry
required in PC-based ion analysers?
a) Hardware set-up
b) Signal measurement
c) Calibration
d) Sample calculation
A
c) Calibration
88
Q
- The analog and digital grounds are connected together
in ion analysers.
a) True
b) False
A
b) False
89
Q
- Which of the following is not a characteristic of the
immobilized enzymes?
a) They cannot be re-used
b) It produces reproducible results
c) Stability exists
d) Same catalytic activity is present for number of analysis
A
c) Stability exists
90
Q
- Which of the following is not a characteristic of the
immobilized enzymes?
a) They cannot be re-used
b) It produces reproducible results
c) Stability exists
d) Same catalytic activity is present for number of analysis
A
a) They cannot be re-used
91
Q
- Which of the following is the physico-chemical
component?
a) Enzymes
b) Anti-bodies
c) Transducer
d) Cells or tissues
A
c) Transducer
92
Q
- An example of biosensor, urea electrode makes use of
which of the following electrodes?
a) Carbon dioxide electrode
b) Ammonia electrode
c) Fluoride electrode
d) Ammonium electrode
A
d) Ammonium electrode
93
Q
- In glucose electrode, glucose oxidase has been coupled to an electrode by which of the following materials?
a) Ferrocene derivatives
b) Urease
c) Polyacrylamide
d) Biochips
A
a) Ferrocene derivatives
94
Q
- Biosensors measure glucose concentrations between which of the following ranges?
a) 10-1 to 10-2 M
b) 10-2 to 10-4 M
c) 10-1 to 10-4 M
d) 10-1 to 10-7 M
A
d) 10-1 to 10-7 M
95
Q
- Transducers employed in the bulk of enzyme electrodes use which of the following principles?
a) Amperometric
b) Optical
c) Magnetic
d) Colorimetric
A
a) Amperometric
96
Q
- Which of these biosensors use the principle of heat
released or absorbed by a reaction?
a) Potentiometric biosensor
b) Optical biosensors
c) Piezo-electric biosensors
d) Calorimetric biosensors
A
d) Calorimetric biosensors
97
Q
- Which of the following biosensors use the movement of electrons produced during redox reactions?
a) Amperometric biosensor
b) Potentiometric biosensors
c) Piezo-electric biosensors
A
a) Amperometric biosensor
98
Q
- Nanoscopic optical biosensors have fast response time but the sensitivity is reduced.
a) True
b) False
A
b) False
99
Q
- In glucose sensor, a measure of change in oxygen value is a measure of the glucose value.
a) True
b) False
A
a) True
100
Q
- For constructing the glucose sensor, which of the
following is used as a gel?
a) Urea
b) Urease
c) Acrylamide
d) Polyacrylamide
A
d) Polyacrylamide
