Analytical instruments are very important in process industries such as water treatment, oil & gas, pharmaceuticals, food & beverage, and chemical manufacturing. Analytical instruments help monitor and control key quality parameters like pH, conductivity, density, oxidation-reduction potential (ORP), humidity and turbidity.
pH analyzers are used to check acidity or alkalinity in chemical processes.
Conductivity meters help assess water purity and ion concentration.
Density meters monitor the concentration and mixing quality of liquids.
ORP sensors evaluate oxidation–reduction status, especially in disinfection and wastewater applications.
Humidity sensors measure moisture in air, vital for HVAC and drying units. Turbidity meters measure clarity of water by detecting suspended particles in filtration systems.
To help you strengthen your knowledge, we have compiled 100 questions with answers and explanations based on real industrial applications. This set is ideal for interview preparation, certification exams, college studies and practical field training.
Let’s get started!
100 Analytical Instruments Questions & Answers
Q1. What does a pH meter measure?
a) Hydrogen ion concentration
b) Oxygen saturation
c) Chlorine content
d) Solvent density
Correct Answer: a
Explanation: pH indicates acidity/alkalinity based on hydrogen ion activity measured by a glass electrode.
Q2. Conductivity of water mainly depends on:
a) Dissolved ionic concentration
b) Water color
c) Ambient pressure
d) Oil content
Correct Answer: a
Explanation: More ions → higher conductivity. Pure water has very low conductivity.
Q3. In analytical instruments ORP stands for:
a) Oxygen Reduction Percentage
b) Oxidation–Reduction Potential
c) Organic Reaction Process
d) Oil Retention Parameter
Correct Answer: b
Explanation: ORP measures electron transfer ability of a solution—indicator of oxidizing or reducing conditions.
Q4. Turbidity is measured in:
a) %RH
b) NTU
c) ppm
d) pH units
Correct Answer: b
Explanation: Nephelometric Turbidity Units (NTU) represent suspended particle concentration by light scattering.
Q5. The standard reference electrode in pH meters is typically:
a) Silver chloride electrode
b) Glass electrode
c) Oxygen sensor
d) Ion selective membrane
Correct Answer: a
Explanation: pH meters use a glass electrode + Ag/AgCl reference electrode pair for stable measurement.
Q6. Conductivity measurement units are usually in:
a) NTU
b) µS/cm or mS/cm
c) ppm
d) Lux
Correct Answer: b
Explanation: Siemens per centimeter (S/cm) represents electrical conduction through water.
Q7. Which property does a density meter (densitometer) measure?
a) Mass per unit volume
b) Ion activity
c) Gas pressure
d) Color intensity
Correct Answer: a
Explanation: Density meters determine compactness of matter (kg/m³ or g/cm³).
Q8. High ORP value means the solution is:
a) Strongly reducing
b) Strongly oxidizing
c) Highly saline
d) Free of particles
Correct Answer: b
Explanation: Oxidizing solutions (like chlorinated water) show higher positive ORP values.
Q9. Which instrument measures relative humidity in analytical instruments?
a) Anemometer
b) Hygrometer
c) Refractometer
d) Pycnometer
Correct Answer: b
Explanation: A hygrometer measures the moisture content of air (RH%).
Q10. Turbidity meters work on the principle of:
a) Conductivity change
b) Light scattering by suspended particles
c) Gas ionization
d) Vibration frequency
Correct Answer: b
Explanation: More particles → more scattering → higher turbidity value.
Q11. pH scale ranges from:
a) 1 to 100
b) 0 to 14
c) -10 to +10
d) 0 to 100%
Correct Answer: b
Explanation: Below 7 = acidic, above 7 = alkaline, 7 = neutral.
Q12. The principle used in vibrating element density meters:
a) Temperature expansion
b) Change in resonant frequency
c) Ion exchange
d) Radiation absorption
Correct Answer: b
Explanation: Density change alters mass load and vibration frequency of sensor tube.
Q13. Conductivity sensors are typically made of:
a) Plastic only
b) Graphite or stainless steel electrodes
c) Magnet plates
d) Glass capillary
Correct Answer: b
Explanation: Electrodes help conduct ions in solution for measurement.
Q14. ORP electrodes are made of:
a) Gold or Platinum
b) Paper
c) Rubber
d) Aluminum
Correct Answer: a
Explanation: Noble metals enable better electron exchange during redox reaction sensing.
Q15. Relative Humidity (RH) is defined as:
a) Ratio of air temperature to pressure
b) Ratio of water vapor to saturated vapor at same temp
c) Ratio of CO₂ to air
d) Dewpoint divided by temperature
Correct Answer: b
Explanation: RH indicates moisture holding level of air relative to its saturation point.
Q16. Calibration of turbidity meters uses:
a) Buffer solutions
b) Formazin standards
c) Salinity standards
d) Compressed air
Correct Answer: b
Explanation: Formazin gives repeatable light-scattering properties for turbidity calibration.
Q17. The typical response time of a pH electrode depends on:
a) Ion diffusion through glass membrane
b) Battery size
c) Electrode color
d) Mechanical vibration
Correct Answer: a
Explanation: Quick equilibrium between internal and external hydrogen ions gives accurate readings.
Q18. High conductivity in boiler water indicates:
a) Good water quality
b) High dissolved impurities
c) High oxygen content only
d) High dewpoint
Correct Answer: b
Explanation: Conductivity monitoring prevents scale/corrosion in industrial boilers.
Q19. Dew point is a term associated with:
a) Density measurement
b) Humidity measurement
c) pH measurement
d) Salinity measurement
Correct Answer: b
Explanation: Dew point is temperature at which water vapor condenses—indicates humidity level.
Q20. A nephelometer measures turbidity by detecting:
a) Reflected light at 90°
b) Magnetic fields
c) Oxygen diffusion
d) Sound waves
Correct Answer: a
Explanation: 90-degree scattered light measurement gives high sensitivity to fine particles.
Q21. What type of electrode is primarily used in pH sensors for output stability?
a) Platinum electrode
b) Reference electrode (Ag/AgCl)
c) Carbon rod electrode
d) Thermocouple electrode
Correct Answer: b
Explanation: The Ag/AgCl reference electrode provides a constant potential to compare the glass electrode signal.
Q22. The most accurate temperature compensation in conductivity measurement is achieved by:
a) Manual adjustment
b) Automatic temperature compensation (ATC)
c) Removing temperature effect
d) Using ice water
Correct Answer: b
Explanation: ATC corrects conductivity values to a standard reference temperature (usually 25°C).
Q23. What does a high positive ORP value indicate in water treatment?
a) Strong reducing conditions
b) Strong oxidizing conditions
c) Low disinfection
d) High viscosity
Correct Answer: b
Explanation: Positive ORP means strong oxidizers like chlorine are present, improving disinfection.
Q24. Density measurement using Coriolis principle mainly depends on:
a) Electromagnetic field change
b) Tube vibration frequency shift
c) Reaction with chemical reagent
d) Gas diffusion
Correct Answer: b
Explanation: Fluid density changes the vibration frequency of the flow tube inside Coriolis meters.
Q25. In pH measurement, what is the role of the hydration layer on the glass electrode?
a) Prevent corrosion
b) Enable ion exchange for accurate reading
c) Improve conductivity of solution
d) Reduce temperature effect
Correct Answer: b
Explanation: A hydrated gel layer forms on the glass membrane allowing H⁺ ions to exchange during pH measurement.
Q26. Conductivity sensors may show incorrect values due to:
a) Air bubbles on electrodes
b) Proper cleaning
c) Correct cell constant
d) Stable temperature
Correct Answer: a
Explanation: Air reduces electrode contact with the solution and increases measurement error.
Q27. The relative humidity is expressed as:
a) % of dew point achieved
b) Ratio of actual vapor to saturated vapor × 100
c) Speed of air flow
d) Mass of air
Correct Answer: b
Explanation: RH quantifies moisture content relative to maximum moisture-holding capacity.
Q28. The most common pH buffer solutions used for calibration are:
a) pH 4, 7, and 10
b) pH 1, 2, and 3
c) pH 8, 11, and 14
d) pH 0, 6, and 12
Correct Answer: a
Explanation: These buffers cover acidic, neutral, and alkaline ranges for accurate calibration.
Q29. In analytical instruments, Conductivity cell constant (K) depends on:
a) Electrode geometry and spacing
b) Color of electrodes
c) Chemical composition of sample
d) Pressure
Correct Answer: a
Explanation: Proper distance and area between electrodes determine sensitivity to ionic conduction.
Q30. Which instrument is used for turbidity measurement with highest sensitivity?
a) Absorptiometer
b) Nephelometer
c) Colorimeter
d) Refractometer
Correct Answer: b
Explanation: Nephelometers detect scattered light at 90°, ideal for low turbidity levels.
Q31. ORP electrodes are commonly used in:
a) Boiler water only
b) Disinfection and wastewater treatment
c) Gas chromatography
d) Pressure control
Correct Answer: b
Explanation: ORP monitors redox reactions, especially chlorine disinfection efficiency.
Q32. A vibrating fork density meter works by:
a) Measuring sound velocity
b) Detecting change in vibration damping
c) Calculating color changes
d) Measuring CO₂ levels
Correct Answer: b
Explanation: Fluid density changes fork vibration frequency and damping characteristics.
Q33. pH value of strong alkaline solution (like NaOH) is typically:
a) Less than 4
b) Equal to 7
c) More than 7
d) Exactly 14 always
Correct Answer: c
Explanation: Alkaline solutions have a pH > 7; the exact value depends on concentration.
Q34. Conductivity in natural water increases with:
a) Pure H₂O only
b) Dissolved salts and minerals
c) Removing ions
d) Adding oil
Correct Answer: b
Explanation: More dissolved ionic compounds like Na⁺, Cl⁻ increase conductivity.
Q35. Dew point can be applied as an indicator of:
a) Conductivity
b) Humidity level in gases
c) Reducing potential
d) Water pH
Correct Answer: b
Explanation: Dew point temperature is directly related to moisture content in air.
Q36. In analytical instruments Turbidity increases when:
a) Suspended particles decrease
b) More fine particles scatter light
c) Water becomes distilled
d) Light intensity becomes zero
Correct Answer: b
Explanation: Fine particles increase scattering and reduce water clarity.
Q37. pH electrode lifespan can reduce faster due to:
a) Proper storage
b) Cleaning with deionized water
c) Exposure to high temperature/strong chemicals
d) Regular calibration
Correct Answer: c
Explanation: Harsh conditions degrade the glass membrane and hydration layer.
Q38. Conductivity is mostly used as a quick test for:
a) Chemical purity of water
b) Oil viscosity
c) Air pollution
d) Density of gas
Correct Answer: a
Explanation: Low conductivity indicates purer water with minimal ionic contamination.
Q39. In analytical instrument, ORP measurement unit is:
a) Ampere
b) Volt (mV)
c) Lux
d) NTU
Correct Answer: b
Explanation: ORP values are displayed in millivolts representing oxidation/reduction potential.
Q40. Density instruments in breweries help to measure:
a) Sugar content in fermentation
b) ORP value
c) Turbidity only
d) Ambient humidity
Correct Answer: a
Explanation: Density correlates to sugar level → fermentation progress and alcohol content.
Q41. What happens to pH if hydrogen ion concentration increases?
a) pH increases
b) pH decreases
c) pH becomes constant
d) pH becomes zero always
Correct Answer: b
Explanation: pH is inversely related to hydrogen ion concentration; more H⁺ → lower pH → more acidic.
Q42. Which type of conductivity principle is used for highly contaminated liquids?
a) Contact electrode conductivity
b) Electromagnetic induction conductivity
c) Optical sensing
d) Ultrasonic sensing
Correct Answer: b
Explanation: Inductive sensors avoid electrode fouling and are ideal for high-conductivity / corrosive media.
Q43. Which parameter is monitored using dew point sensors?
a) Turbidity in liquids
b) Humidity in gases
c) pH of water
d) Density of oil
Correct Answer: b
Explanation: Dew point indicates the temperature at which moisture condenses → measures humidity content in gases.
Q44. Density measurement of liquids becomes difficult when:
a) Temperature fluctuates rapidly
b) Fluid is transparent
c) Fluid is neutral
d) Sample is at room temperature
Correct Answer: a
Explanation: Density varies with temperature; poor compensation causes large error.
Q45. Which electrode provides fast response and high accuracy in ORP measurement?
a) Aluminum electrode
b) Graphite electrode
c) Platinum or Gold electrode
d) Mercury electrode
Correct Answer: c
Explanation: Noble metals resist corrosion and transfer electrons efficiently.
Q46. In analytical instruments Conductivity in deionized water is:
a) Very high
b) Very low
c) Equal to seawater
d) Same as distilled water
Correct Answer: b
Explanation: Very few dissolved ions → extremely low conductivity, typically < 1 µS/cm.
Q47. Turbidity in drinking water indicates:
a) Microbial contamination possibility
b) High pH
c) Strong acidity
d) Zero suspended solids always
Correct Answer: a
Explanation: Suspended solids increase turbidity and may harbor pathogens.
Q48. What is the ideal storage condition for a pH electrode?
a) Dry in air
b) Stored in pH 4 or storage solution
c) In hot water
d) In 100% ethanol
Correct Answer: b
Explanation: The glass membrane must remain hydrated for accurate ion exchange.
Q49. The conductivity of seawater falls in the range of:
a) 0–10 µS/cm
b) 1–10 mS/cm
c) 100–500 µS/cm
d) 50–100 µS/cm
Correct Answer: b
Explanation: Seawater has high dissolved salts, typically around 50–60 mS/cm.
Q50. A higher density liquid will:
a) Have less mass per unit volume
b) Float above less dense liquids
c) Sink below lower density liquids
d) Have no effect in mixing
Correct Answer: c
Explanation: Higher density = heavier per unit volume → settles below lighter fluids.
Q51. In analytical instruments, ORP measurement helps in monitoring:
a) Chlorine disinfection in water
b) Ambient noise
c) Boiler steam pressure
d) Liquid level in tanks
Correct Answer: a
Explanation: ORP ensures sufficient oxidizing conditions to kill microorganisms.
Q52. Which physical property does a humidity sensor detect?
a) Vibration
b) Moisture in the air
c) pH of soil
d) Electrical noise
Correct Answer: b
Explanation: Humidity sensors measure the water vapor present in the atmosphere.
Q53. The slope of a healthy pH electrode according to Nernst equation is approx.:
a) 5 mV/pH
b) 59 mV/pH at 25°C
c) 100 mV/pH
d) 150 mV/pH
Correct Answer: b
Explanation: The theoretical Nernst slope is about 59.16 mV per pH unit at 25°C.
Q54. Conductivity sensors often require cleaning due to:
a) Electrode fouling from deposits
b) Radioactive decay
c) Change in air pressure
d) Lower ATC settings
Correct Answer: a
Explanation: Coatings and scaling reduce contact between electrodes and solution.
Q55. Turbid water appears:
a) Crystal clear
b) Cloudy due to suspended solids
c) Completely colorless always
d) Highly acidic
Correct Answer: b
Explanation: Scattering of light by particles makes water look cloudy.
Q56. Density decreases when:
a) Temperature increases
b) Solute concentration increases
c) Pressure increases
d) Freezing occurs
Correct Answer: a
Explanation: Heating expands material → volume increases → density decreases.
Q57. ORP and pH together give better insight into:
a) Only acidity
b) Oxidation–reduction and chemical balance
c) Air humidity
d) Solid density
Correct Answer: b
Explanation: Both parameters indicate the chemical state and reaction nature of a solution.
Q58. Common unit used to measure humidity in air:
a) NTU
b) %RH
c) mS/cm
d) kg/m³
Correct Answer: b
Explanation: Relative Humidity shows moisture percentage in the air.
Q59. Conductivity calibration involves:
a) Standard KCl solution
b) Formazin solution
c) pH buffer only
d) Turbidity reference
Correct Answer: a
Explanation: Known KCl solutions provide accurate reference conductivity values.
Q60. A density meter is used in chemical industries for:
a) Monitoring concentration of solutions
b) Measuring electrical insulation
c) Measuring turbidity
d) Recording ORP
Correct Answer: a
Explanation: Density indicates solute concentration widely used for acids, brine, and solvents.
Q61. When a pH electrode ages, its response typically becomes:
a) Faster and more accurate
b) Slower with reduced slope
c) Stronger in alkaline conditions
d) Completely insensitive to temperature
Correct Answer: b
Explanation: Aging causes reduced ion mobility and weakens the electrode’s Nernst response.
Q62. Conductivity is directly proportional to:
a) Number of dissolved ions in solution
b) Temperature decrease
c) Turbidity increase
d) ORP value
Correct Answer: a
Explanation: More ions → more charge carriers → better conductivity.
Q63. ORP sensors are mostly used in which industry for oxidation control?
a) Textile
b) Wastewater treatment and chlorination
c) Automotive
d) HVAC
Correct Answer: b
Explanation: ORP ensures ideal conditions for disinfection, especially chlorine dosing.
Q64. Density of a liquid usually increases with:
a) Heating
b) Dissolving solids
c) Reducing pressure
d) Aeration of solution
Correct Answer: b
Explanation: More solute mass per unit volume → higher density (until saturation).
Q65. pH of pure water at 25°C is:
a) 1
b) 7
c) 14
d) 0
Correct Answer: b
Explanation: Pure water is neutral with equal H⁺ and OH⁻ ion concentrations.
Q66. Conductivity meters installed inline require:
a) No calibration ever
b) Cleaning and periodic calibration
c) No temperature compensation
d) No sensor cable
Correct Answer: b
Explanation: Scaling or fouling changes readings; calibration ensures correct values.
Q67. Which factor influences humidity measurement accuracy?
a) Light color
b) Sensor contamination & temperature stability
c) Pressure gauge reading
d) Cable resistance
Correct Answer: b
Explanation: Temperature fluctuations and dust on sensor materials affect readings.
Q68. High turbidity can negatively impact:
a) UV disinfection efficiency
b) Electrical wiring
c) Atmospheric pressure
d) Fuel octane rating
Correct Answer: a
Explanation: Suspended particles block UV light and shield microbes from sterilization.
Q69. The output of a pH meter is in:
a) Microampere
b) Millivolts
c) Newtons
d) NTU
Correct Answer: b
Explanation: pH meters measure EMF difference in millivolts, later converted to pH.
Q70. Conductivity increases with temperature because:
a) Ions move faster
b) Surface tension increases
c) Sample becomes highly acidic
d) Electrode expands
Correct Answer: a
Explanation: Higher temperature = higher ion mobility and conduction capability.
Q71. In beer manufacturing, ORP is used to monitor:
a) Fermentation oxidation
b) Bottle weight
c) Label quality
d) Turbidity of air
Correct Answer: a
Explanation: ORP helps control oxidation during brewing and fermentation stages.
Q72. Density measurement helps to determine:
a) Color concentration
b) Fluid identification and mixture ratio
c) Electrical power usage
d) UV absorbance
Correct Answer: b
Explanation: Density difference reveals fluid type and strength of mixing components.
Q73. When measuring pH of hot liquids, error may occur due to:
a) Sensor hydration
b) Temperature effect on electrode potential
c) Increased ORP
d) Light reflection
Correct Answer: b
Explanation: Glass electrode voltage changes with temperature → compensation required.
Q74. Conductivity probes with 2-electrodes are suitable for:
a) Highly fouling media
b) Low conductivity applications
c) Measuring oxygen
d) Non-aqueous liquids
Correct Answer: b
Explanation: Two-electrode probes are best for pure/low-ion water.
Q75. Humidity sensor calibration uses:
a) Standard salt solutions
b) KCl conductivity standards
c) pH buffers only
d) Formazin solution
Correct Answer: a
Explanation: Certain salts create stable humidity levels inside sealed chambers.
Q76. Turbidity should be monitored in filtration processes to:
a) Increase mineral content
b) Verify clarity and filter performance
c) Reduce gas flow
d) Increase density
Correct Answer: b
Explanation: High turbidity indicates filter failure or breakthrough.
Q77. pH measurement in seawater requires special electrodes due to:
a) Lack of ions
b) High sodium ion interference
c) High oxide content
d) Rainwater influence
Correct Answer: b
Explanation: High Na⁺ levels interfere with glass membrane causing sodium error.
Q78. Conductivity meters are commonly used in power plants to monitor:
a) Drum water purity and steam leaks
b) Valve torque
c) Flame temperature
d) Vibration level
Correct Answer: a
Explanation: Keeps boiler water ionic contamination under control to prevent corrosion.
Q79. Liquids with suspended solids cause density meters to:
a) Read lower accuracy due to disturbances
b) Work better
c) Measure pH
d) Increase response speed
Correct Answer: a
Explanation: Non-uniform sample composition disturbs vibration frequency readings.
Q80. ORP sensors must be kept:
a) Dry when not in use
b) Hydrated like pH sensors
c) Heated continuously
d) Without electrolyte
Correct Answer: b
Explanation: Hydration maintains proper ion and electron transfer ability.
Q81. pH sensor output becomes noisy mainly due to:
a) Proper grounding
b) Electrical interference and cable damage
c) High-quality transmitter
d) Clean electrodes
Correct Answer: b
Explanation: Damaged cables and electrical noise affect millivolt signals, making pH unstable.
Q82. Conductivity readings can be falsely low if:
a) Electrode is clean
b) Solution temperature is high
c) Air bubbles coat the sensor
d) Proper ATC is enabled
Correct Answer: c
Explanation: Bubbles reduce electrode contact → lower conductivity reading.
Q83. ORP values below 0 mV indicate:
a) Strong reduction potential
b) Strong oxidation
c) No chemical reaction
d) Constant pH
Correct Answer: a
Explanation: Negative values show reducing agents like sulfides are dominant.
Q84. Density of a liquid is usually expressed in:
a) %RH
b) g/cm³ or kg/m³
c) mS/cm
d) NTU
Correct Answer: b
Explanation: Mass per unit volume is standard density expression.
Q85. pH electrodes need regular replacement because:
a) Glass membrane degrades over time
b) Reference electrodes become transparent
c) Electrolyte turns into gas
d) Cable becomes longer
Correct Answer: a
Explanation: Reduced sensitivity and slower response require electrode replacement.
Q86. Conductivity cells are selected based on:
a) Cell constant (K value)
b) Electrode paint color
c) Cable temperature rating only
d) NTU value
Correct Answer: a
Explanation: K value defines the measurement range (low, medium, high conductivity).
Q87. ORP measurement in swimming pools ensures:
a) Perfect water clarity
b) Correct chlorine effectiveness
c) Pressure difference control
d) pH probe protection
Correct Answer: b
Explanation: Good ORP confirms disinfectant performance even if water looks clear.
Q88. When density increases due to added solutes, the solution becomes:
a) Less concentrated
b) More concentrated
c) Neutral in nature
d) Perfectly pure
Correct Answer: b
Explanation: More solute mass → higher density → higher concentration.
Q89. Excessive humidity may cause:
a) Static electricity increase
b) Condensation and corrosion of devices
c) No effect on electronics
d) Improved insulation
Correct Answer: b
Explanation: Moisture accelerates rusting and electronic malfunctioning.
Q90. Turbidity increases with:
a) Removal of solids
b) Chemical precipitation of fine particles
c) Increasing suspended solids in water
d) Lowering of flow velocity
Correct Answer: c
Explanation: Higher solid content → increased light scattering → more NTU.
Q91. pH measurement in high-purity water is difficult due to:
a) High ionic strength
b) Very low conductivity causing unstable readings
c) Strong color
d) High turbidity
Correct Answer: b
Explanation: Lack of ions causes slow response and high electrical noise sensitivity.
Q92. Conductivity is not suitable for:
a) Estimating dissolved ion concentration
b) Pure water quality monitoring
c) Redox reaction analysis
d) Salinity checks
Correct Answer: c
Explanation: Conductivity doesn’t give info on oxidation or reduction processes.
Q93. ORP sensor drift can be corrected by:
a) Electrode polishing and regeneration
b) Ignoring calibration
c) Turning off transmitter
d) Using pH buffer
Correct Answer: a
Explanation: Cleaning and refresh solutions recover electrode performance.
Q94. Density measurement helps detect:
a) Pipe leakage
b) Wrong product mixing in pipelines
c) Cable damage
d) Air humidity
Correct Answer: b
Explanation: Change in density indicates material switching during batching.
Q95. Humidity sensors are often used in:
a) Drying processes and HVAC systems
b) Diesel fuel measurement
c) UV turbidity meters
d) Boiler water conductivity
Correct Answer: a
Explanation: Optimal humidity ensures accurate drying and comfortable indoor environment.
Q96. Turbidity meters require:
a) Lens cleaning to avoid light blockage
b) No maintenance
c) Constant heating
d) High-pressure protection only
Correct Answer: a
Explanation: Dirt obscures optics and gives false high readings.
Q97. pH and ORP sensors both contain:
a) Reference electrode system
b) Thermocouple tip
c) CO₂ chamber
d) Turbidity lens
Correct Answer: a
Explanation: Reference electrode ensures stable potential for both measurements.
Q98. Conductivity measurement is affected by sample:
a) Ion type and concentration
b) Color only
c) Light scattering
d) Room decoration
Correct Answer: a
Explanation: Multivalent ions conduct differently than monovalent ions.
Q99. In slurry applications, density meters help monitor:
a) Solids concentration
b) Ambient humidity
c) Oxidation state
d) UV light level
Correct Answer: a
Explanation: Solid content addition increases slurry density — used in mining and wastewater.
Q100. Turbidity measurement is important in wastewater discharge to:
a) Increase COD
b) Verify compliance with environmental standards
c) Reduce density
d) Increase chlorine demand
Correct Answer: b
Explanation: Regulated turbidity ensures safe effluent quality before release.
What we learn today?
Analytical instruments help monitor and improve the quality of industrial processes.
By measuring critical parameters such as pH, conductivity, density, ORP, humidity, and turbidity, these instruments ensure product consistency, safety, and environmental compliance.
They play a very important role in water treatment, pharmaceuticals, food processing, chemical manufacturing, and various process industries.
A strong understanding of analytical measurements helps instrumentation technicians troubleshoot issues quickly and keep operations optimized.
Mastering these concepts not only improves process performance but also enhances professional growth in the instrumentation field.
Frequently Asked Questions – Analytical Instruments
1️⃣ What are analytical instruments in the process industry?
Analytical instruments are devices used to measure chemical and physical properties such as pH, conductivity, density, ORP, humidity, and turbidity. They ensure product quality, process efficiency, and environmental compliance.
2️⃣ Why are analytical instruments important?
Analytical instruments provide real-time insights into the chemical condition of a process. They help identify contamination, maintain proper treatment levels, and keep operations within safe and regulatory limits.
3️⃣ Where are analytical instruments commonly used?
These instruments are widely used in water and wastewater treatment, food and beverage manufacturing, pharmaceuticals, oil & gas, power plants, and chemical industries.
4️⃣ What are the most common types of analytical instruments?
The most common analytical instruments include:
1) pH meters
2) Conductivity analyzers
3) Density meters
4) ORP sensors
5) Humidity transmitters
6) Turbidity meters
5️⃣ How often should analytical instruments be calibrated?
Calibration frequency depends on the instrument type and application. In critical process environments, calibration may be required weekly or monthly. Proper maintenance ensures accuracy and reliable measurement.
6️⃣ What skills are needed to operate analytical instruments?
Technicians must understand instrument principles, calibration methods, sensor maintenance, troubleshooting techniques, and process application requirements to ensure accurate measurement and reliable performance.
I hope you like above blog. There is no cost associated in sharing the article in your social media. Thanks for Reading !! Happy Learning
