30+ QC Chemist Interview Questions and Answers for Freshers

SOP applications ensure proper instrument operation in QC chemistry.

• SOPs outline step-by-step procedures for instrument use and maintenance.

• SOPs should be regularly reviewed and updated as needed.

• Examples of SOPs include calibration procedures, cleaning protocols, and troubleshooting guides.

Water analysis is the process of identifying and measuring the chemical compounds present in water.

• Water analysis is important for ensuring the safety and quality of drinking water.

• It involves testing for various parameters such as pH, dissolved oxygen, turbidity, and total dissolved solids.

• Water analysis can also be used to monitor the levels of pollutants and contaminants in water sources.

• Examples of chemical compounds that may be tested for include nitrates, phosphates, me...read more

Carbon, sulfur, and phosphorus play important roles in steel making.

• Carbon is a key element in steel making as it determines the hardness and strength of the steel.

• Sulfur is considered an impurity in steel making and needs to be controlled as it can cause brittleness.

• Phosphorus is also an impurity and needs to be minimized as it can reduce the toughness and ductility of steel.

• Carbon is added to steel in the form of coke or coal during the smelting process.

• Sulfur is usually co...read more

Titration is a technique to determine the concentration of a substance in a solution. pH is a measure of acidity or basicity of a solution.

• Titration involves adding a solution of known concentration to a solution of unknown concentration until the reaction is complete.

• pH is measured on a scale of 0-14, with 7 being neutral, below 7 acidic, and above 7 basic.

• Titration can be used to determine the concentration of acids, bases, and other substances in a solution.

• pH is important...read more

Chromatography techniques separate and analyze mixtures based on their physical and chemical properties.

• Gas chromatography (GC)

• Liquid chromatography (LC)

• Ion exchange chromatography (IEC)

• Size exclusion chromatography (SEC)

• Affinity chromatography (AC)

• Thin layer chromatography (TLC)

Sponge iron is a form of iron produced from iron ore. It is used as a raw material in steel making.

• Sponge iron is produced by reducing iron ore in the form of lumps or pellets with a reducing agent such as coal or natural gas.

• It is called 'sponge iron' because it has a spongy appearance due to the presence of pores and voids.

• Sponge iron is highly porous and has a high surface area, which makes it an ideal raw material for steel making.

• It is used in the production of steel thr...read more

PH is a measure of acidity or alkalinity of a solution. It ranges from 0 to 14.

• PH stands for 'potential of hydrogen'

• It is measured on a scale of 0 to 14

• A pH of 7 is considered neutral, below 7 is acidic, and above 7 is alkaline

• PH is important in many industries including food, pharmaceuticals, and water treatment

DT, HPLC, and Karl Fisher titration are analytical techniques used in chemistry.

• DT (Differential Thermal Analysis) is used to measure the temperature difference between a sample and a reference material as they are heated or cooled.

• HPLC (High Performance Liquid Chromatography) is a technique used to separate, identify, and quantify components in a mixture.

• Karl Fisher titration is a method used to determine the amount of water present in a sample by reacting it with iodine and...read more

Molecular weights of HCl and sulfuric acid are 36.46 g/mol and 98.08 g/mol respectively.

• HCl has one hydrogen atom and one chlorine atom, with a molecular weight of 36.46 g/mol.

• Sulfuric acid has two hydrogen atoms, one sulfur atom, and four oxygen atoms, with a molecular weight of 98.08 g/mol.

• Molecular weight is calculated by adding the atomic weights of all the atoms in a molecule.

The principles of HPLC, GC, UV, and IR are the fundamental concepts that govern the operation of these analytical techniques.

• HPLC (High-Performance Liquid Chromatography) separates components of a mixture based on their interactions with a stationary phase and a mobile phase.

• GC (Gas Chromatography) separates components of a mixture based on their boiling points and interactions with a stationary phase and a mobile phase.

• UV (Ultraviolet) spectroscopy measures the absorption of...read more

To prepare a sol of known concentration, weigh the required amount of solute and dissolve it in a known volume of solvent.

• Determine the required concentration and volume of the solute and solvent

• Weigh the required amount of solute using a balance

• Dissolve the solute in a known volume of solvent, using a volumetric flask or pipette

• Mix the solution thoroughly to ensure homogeneity

• Verify the concentration using analytical techniques such as titration or spectrophotometry

Chemistry is the scientific study of matter and its properties, composition, and behavior. QC stands for Quality Control. HPLC and GC are analytical techniques used in chemistry.

• Chemistry is the study of matter and its properties

• QC stands for Quality Control and is used to ensure that products meet certain standards

• HPLC (High Performance Liquid Chromatography) is a technique used to separate, identify, and quantify components in a mixture

• GC (Gas Chromatography) is a technique...read more

Chromatography is a technique used to separate and analyze mixtures. pH is a measure of acidity or basicity. Titration is a method to determine the concentration of a substance in a solution.

• Chromatography involves passing a mixture through a stationary phase and a mobile phase to separate its components. Examples include gas chromatography and liquid chromatography.

• pH is measured on a scale of 0-14, with 7 being neutral. Acids have a pH below 7, while bases have a pH above 7...read more

TDS stands for Total Dissolved Solids. It refers to the total amount of inorganic and organic substances present in water.

• TDS is a measure of the concentration of dissolved solids in water.

• It includes both organic and inorganic substances such as minerals, salts, and metals.

• TDS is usually measured in parts per million (ppm) or milligrams per liter (mg/L).

• The acceptable TDS level for drinking water is generally below 500 ppm.

• High TDS levels can affect the taste, odor, and colo...read more

A pH meter is an electronic device used to measure the acidity or alkalinity of a solution.

• pH meter measures the concentration of hydrogen ions in a solution

• The range of a pH meter is typically from 0 to 14

• A pH of 7 is considered neutral, below 7 is acidic, and above 7 is alkaline

• pH meters are commonly used in chemistry, biology, and environmental science

FTIR is used to determine the functional groups present in the API.

• FTIR measures the absorption of infrared radiation by the sample

• Different functional groups absorb at different wavelengths

• The resulting spectrum can be used to identify the API and its purity

• Examples of functional groups include carbonyl, hydroxyl, and amine groups

pH is a measure of the acidity or basicity of a solution. A buffer solution is a solution that resists changes in pH.

• pH is measured on a scale of 0-14, with 7 being neutral

• Acidic solutions have a pH below 7, while basic solutions have a pH above 7

• Buffer solutions are made up of a weak acid and its conjugate base, or a weak base and its conjugate acid

• Buffer solutions resist changes in pH when small amounts of acid or base are added

There are several types of titrations, including acid-base, redox, complexometric, precipitation, and non-aqueous titrations.

• Acid-base titrations involve the use of an acid or base to neutralize a sample.

• Redox titrations involve the transfer of electrons between reactants.

• Complexometric titrations involve the formation of a complex between a metal ion and a ligand.

• Precipitation titrations involve the formation of a precipitate.

• Non-aqueous titrations involve the use of solvent...read more

API stands for Active Pharmaceutical Ingredient, RAW material refers to the basic materials used in manufacturing, and KSM stands for Key Starting Material.

• API is the main ingredient in a drug that produces the intended effect

• RAW materials are the basic materials used in the manufacturing process of a drug

• KSM is the starting material used in the synthesis of an API

• Examples of RAW materials include solvents, excipients, and reagents

• Examples of KSM include intermediates and bui...read more

Reverse phase HPLC is a chromatographic technique used to separate non-polar compounds based on their hydrophobicity.

• Reverse phase HPLC uses a non-polar stationary phase and a polar mobile phase.

• Non-polar compounds elute first, while polar compounds are retained longer.

• It is commonly used in pharmaceutical analysis to determine drug purity and impurities.

• Example: Separation of a mixture of non-polar drugs like benzodiazepines.

Melting point is the temperature at which a solid substance turns into a liquid. Boiling point is the temperature at which a liquid substance turns into a gas.

• Melting point is a physical property of a substance

• It is the temperature at which the solid and liquid phases of a substance are in equilibrium

• Boiling point is also a physical property of a substance

• It is the temperature at which the vapor pressure of a liquid equals the atmospheric pressure

• Both melting and boiling poin...read more

Beer Lambert law relates the concentration of a substance to the amount of light it absorbs.

• Also known as Beer's law or Lambert-Beer law

• Used in spectroscopy to determine the concentration of a substance in a solution

• States that the absorbance of light is directly proportional to the concentration of the absorbing species

• Can be expressed as A = εcl, where A is absorbance, ε is molar absorptivity, c is concentration, and l is path length

• Used in pharmaceutical analysis to determ...read more

Normality is the concentration of a solution expressed as the number of equivalents of solute per liter of solution. Molarity is the concentration of a solution expressed as the number of moles of solute per liter of solution.

• Normality is a measure of the concentration of a solution in terms of the number of equivalents of solute per liter of solution.

• Molarity is a measure of the concentration of a solution in terms of the number of moles of solute per liter of solution.

• Norma...read more

Normality is a measure of concentration of a solution expressed as the number of equivalents of solute per liter of solution.

• Normality is used in acid-base titrations.

• It is calculated by multiplying the molarity of a solution by the number of equivalents of solute per mole.

• For example, a 1M solution of HCl has a normality of 1N because HCl is a monoprotic acid and has one equivalent per mole.

• However, a 1M solution of H2SO4 has a normality of 2N because H2SO4 is a diprotic aci...read more

Lambert Beers law states that the absorbance of a solution is directly proportional to the concentration of the absorbing species.

• The law is used to determine the concentration of a substance in a solution by measuring its absorbance.

• It assumes that the absorbing species is uniformly distributed throughout the solution.

• The law is often used in spectroscopy and colorimetry.

• The equation for the law is A = εlc, where A is absorbance, ε is the molar absorptivity, l is the path le...read more

I am a highly motivated QC Chemist with 5 years of experience in the pharmaceutical industry.

• I have a Bachelor's degree in Chemistry and a Master's degree in Analytical Chemistry.

• I have experience in method development, validation, and troubleshooting.

• I am proficient in HPLC, GC, and other analytical techniques.

• I am a team player and have excellent communication skills.

• I am passionate about ensuring the quality of pharmaceutical products.

• I am excited to bring my skills and ex...read more

Molarity is a measure of the concentration of a solution in terms of the number of moles of solute per liter of solution.

• Molarity is expressed in units of moles per liter (mol/L).

• It is used to quantify the amount of solute in a solution.

• Molarity can be calculated using the formula: Molarity = moles of solute / liters of solution.

• For example, a solution containing 0.5 moles of sodium chloride in 1 liter of water has a molarity of 0.5 M.

• Molarity is an important concept in chemi...read more

pH is a measure of the acidity or alkalinity of a solution. It indicates the concentration of hydrogen ions in the solution.

• pH is measured on a scale from 0 to 14.

• A pH of 7 is considered neutral, below 7 is acidic, and above 7 is alkaline.

• Lower pH values indicate higher acidity, while higher pH values indicate higher alkalinity.

• pH can be measured using pH meters or pH indicator papers.

• Examples of pH values: lemon juice (pH 2), water (pH 7), baking soda solution (pH 9).

GC stands for Gas Chromatography and HPLC stands for High Performance Liquid Chromatography.

• GC is a technique used to separate and analyze compounds that can be vaporized without decomposition.

• HPLC is a technique used to separate and analyze compounds that are dissolved in a liquid solvent.

• GC is commonly used for volatile compounds like hydrocarbons, while HPLC is used for non-volatile compounds like pharmaceuticals.

• Both techniques involve a stationary phase and a mobile phas...read more

Titration is a technique used to determine the concentration of a substance in a solution by reacting it with a solution of known concentration.

• Acid-base titration

• Redox titration

• Complexometric titration

• Precipitation titration

• Back titration

Chemical expiry date can be checked by looking at the label or packaging.

• Check the label or packaging of the chemical for an expiry date

• Look for any signs of degradation or changes in color/odor

• Consult the manufacturer's guidelines or safety data sheet for expiration information

A pH meter is a scientific instrument used to measure the acidity or alkalinity of a substance.

• Measures the concentration of hydrogen ions in a solution

• Consists of a probe with a glass electrode and a reference electrode

• Calibrated using buffer solutions of known pH values

• Commonly used in laboratories for quality control and research purposes

Yes, I have experience working in the pharmaceutical industry.

• I have worked as a QC Chemist in a pharmaceutical company for 3 years.

• I am familiar with GMP regulations and have experience in analytical method validation.

• I have worked with various analytical instruments such as HPLC, GC, and FTIR.

• I have also conducted stability studies and prepared analytical reports.

PH calibration is the process of adjusting and standardizing a pH meter to ensure accurate and reliable measurements.

• PH calibration involves using buffer solutions with known pH values to adjust the meter readings.

• Calibration should be done regularly to maintain accuracy and reliability.

• The calibration process typically involves adjusting the slope and offset of the pH meter.

• After calibration, the pH meter should be able to accurately measure the pH of unknown solutions.

• Prope...read more