60+ Senior Chemist Interview Questions and Answers

In case of a fire at work, prioritize safety, alert authorities, and use fire extinguishers if trained.

• Stay calm and assess the situation quickly.

• Activate the fire alarm to alert others and call emergency services.

• If safe to do so, use a fire extinguisher on small fires (e.g., Class B for flammable liquids).

• Evacuate the area immediately, following the designated escape routes.

• Do not use elevators; always use stairs to exit.

• If trapped, seal doors with cloth to prevent smoke en...read more

Temperature and pressure are directly related to each other.

• As temperature increases, pressure also increases.

• As temperature decreases, pressure also decreases.

• This relationship is described by the ideal gas law, which states that the pressure of a gas is directly proportional to its temperature when volume and amount of gas are constant.

• For example, when a gas is heated, its molecules gain kinetic energy and move faster, resulting in more frequent collisions with the contain...read more

Yes, I am proficient in MS Office package including Excel, Word, and PowerPoint.

• I have used Excel for data analysis and creating spreadsheets

• I am skilled in creating professional documents using Word

• I have created presentations using PowerPoint for various purposes

• I am familiar with advanced features of MS Office such as macros and pivot tables

Strong acids completely dissociate in water, while weak acids only partially dissociate. Acids include HCl, H2SO4, HNO3, CH3COOH, and H3PO4. Bases include NaOH, KOH, NH3, Ca(OH)2, and Mg(OH)2.

• Strong acids fully dissociate in water, producing a high concentration of H+ ions. Examples include HCl (hydrochloric acid), H2SO4 (sulfuric acid), and HNO3 (nitric acid).

• Weak acids only partially dissociate in water, resulting in a lower concentration of H+ ions. Examples include CH3COO...read more

Preparing a PPM solution involves diluting a stock solution to achieve a specific concentration for ICP OES and AAS analysis.

• Start with a concentrated stock solution of the analyte.

• Calculate the desired concentration in PPM (parts per million).

• Use the formula: C1V1 = C2V2, where C1 is the concentration of the stock, V1 is the volume of stock needed, C2 is the desired concentration, and V2 is the final volume.

• For example, to prepare 100 mL of a 10 PPM solution from a 1000 PPM ...read more

Inventory control in pharma involves managing raw materials, finished products, and packaging materials.

• Use a computerized inventory management system to track inventory levels and reorder points

• Implement a first-in, first-out (FIFO) system to ensure that older inventory is used first

• Regularly conduct physical inventory counts to identify discrepancies and prevent stockouts

• Maintain proper storage conditions to prevent spoilage or degradation of inventory

• Separate and label inv...read more

Yes, I have basic knowledge of safety protocols in the laboratory.

• I am familiar with the proper use of personal protective equipment (PPE) such as gloves, goggles, and lab coats.

• I understand the importance of labeling chemicals and storing them properly.

• I know how to handle and dispose of hazardous waste.

• I am aware of emergency procedures in case of accidents or spills.

• I have received training on fire safety and the use of fire extinguishers.

Reactions involve the transformation of one or more substances into new substances.

• Acid-base reactions involve the transfer of a proton from an acid to a base.

• Oxidation-reduction reactions involve the transfer of electrons between reactants.

• Combustion reactions involve the rapid oxidation of a fuel in the presence of oxygen.

• Hydrolysis reactions involve the breaking of a chemical bond using water.

• Esterification reactions involve the formation of an ester from a carboxylic acid...read more

I handle operations by ensuring compliance with CGMP and GMP standards. I joined your company for its reputation in the industry.

• I handle operations by overseeing production processes to ensure compliance with CGMP (Current Good Manufacturing Practice) standards

• I also ensure adherence to GMP (Good Manufacturing Practice) guidelines to maintain product quality and safety

• I joined your company because of its strong reputation in the industry for upholding high standards of quali...read more

Qualification process for AHU system involves handling of equipment to ensure compliance with standards.

• Qualification process involves testing and verifying the performance of AHU system.

• Equipment handling should follow standard operating procedures to prevent contamination.

• Documentation of the qualification process and equipment handling is necessary for compliance.

• Examples of equipment handling include cleaning, calibration, and maintenance.

• Qualification process should be p...read more

Acids and bases are important in chemistry. Here are some examples:

• Acids: HCl (hydrochloric acid), H2SO4 (sulfuric acid), HNO3 (nitric acid)

• Bases: NaOH (sodium hydroxide), KOH (potassium hydroxide), NH3 (ammonia)

• Acids have a pH less than 7, while bases have a pH greater than 7

• Acids donate H+ ions, while bases accept H+ ions

Alkanity is not directly associated with hardness.

• Alkanity refers to the ability of a substance to neutralize acids.

• Hardness refers to the concentration of calcium and magnesium ions in water.

• Alkanity and hardness are both important water quality parameters, but they measure different properties.

• Alkanity is measured in terms of alkaline substances like bicarbonates, carbonates, and hydroxides.

• Hardness is measured in terms of calcium and magnesium ions.

• While both alkanity and ...read more

The weight of a shoe will change if the specific gravity of the material it is made of changes.

• Specific gravity is the ratio of the density of a material to the density of a reference substance (usually water).

• If the specific gravity of the material increases, the weight of the shoe will also increase.

• Conversely, if the specific gravity decreases, the weight of the shoe will decrease.

• For example, if a shoe is made of a material with a specific gravity of 2 and then it is chan...read more

Fouling refers to the accumulation of unwanted substances on surfaces, hindering their normal function.

• Fouling is the deposition or buildup of unwanted materials on surfaces.

• It can occur in various industries, such as oil refining, chemical processing, and water treatment.

• Examples of fouling include the formation of scale in pipes, the buildup of biofilms on ship hulls, and the accumulation of dirt on solar panels.

• Fouling can reduce efficiency, increase energy consumption, an...read more

As a Sr. Chemist, I handle various types of equipment including spectrophotometers, chromatographs, balances, and reactors.

• Spectrophotometers

• Chromatographs

• Balances

• Reactors

Planning for production involves analyzing demand, setting production goals, scheduling resources, and monitoring progress.

• Analyze market demand and forecast future demand

• Set production goals based on demand and available resources

• Schedule resources such as labor, equipment, and raw materials

• Monitor progress and adjust plans as needed

• Consider factors such as lead times, inventory levels, and production costs

• Use software tools such as ERP systems to aid in planning and schedul...read more

OPC (Ordinary Portland Cement) is a basic cement type, while PPC (Pozzolana Portland Cement) includes pozzolanic materials for enhanced properties.

• OPC is made from limestone and clay, while PPC includes pozzolanic materials like fly ash or volcanic ash.

• PPC has better resistance to chemical attacks compared to OPC, making it suitable for structures exposed to harsh environments.

• PPC has lower heat of hydration, reducing the risk of thermal cracking in large structures.

• OPC is ty...read more

Quality checking in oil can be maintained by following strict protocols and using advanced technology.

• Establishing standard operating procedures for quality control

• Regular testing of oil samples for purity and contaminants

• Using advanced technology such as gas chromatography and mass spectrometry

• Training staff on proper handling and testing techniques

• Maintaining a clean and controlled environment for testing

• Collaborating with external laboratories for third-party verification

• I...read more

I have 5 years of experience in the dairy industry.

• Worked as a chemist at a dairy processing plant for 3 years

• Developed new dairy products and improved existing formulations

• Conducted quality control tests on dairy products

• Collaborated with dairy farmers to ensure quality of raw materials

To check caustic chemical purity, various analytical techniques and methods can be employed to assess composition and concentration.

• Use titration methods to determine the concentration of the caustic substance, such as sodium hydroxide.

• Employ spectroscopy techniques like UV-Vis or FTIR to analyze the chemical structure and identify impurities.

• Conduct chromatography (e.g., HPLC) to separate and quantify different components in the caustic solution.

• Perform pH testing to ensure ...read more

To prepare a 1 ppm boron solution, dissolve a precise amount of boron compound in a specific volume of solvent.

• 1 ppm means 1 mg of solute per liter of solution.

• Choose a boron compound, such as boric acid (H3BO3) or sodium borate (Na2B4O7).

• Weigh 0.1 mg of boron compound for 1 liter of solution.

• Dissolve the compound in distilled water to reach the final volume.

• Use a volumetric flask for accurate measurement.

The Beer-Lambert Law is fundamental to spectrophotometry, relating absorbance to concentration and path length.

• The Beer-Lambert Law states A = εlc, where A is absorbance, ε is molar absorptivity, l is path length, and c is concentration.

• It is used to determine the concentration of a solute in a solution by measuring the light absorbed at a specific wavelength.

• For example, if a solution has an absorbance of 0.5 and the molar absorptivity is known, the concentration can be calc...read more

Chemical composition refers to the types and amounts of elements in a substance, defining its properties and behavior.

• Chemical composition can be expressed in terms of molecular formulas, e.g., H2O for water.

• It includes both the types of atoms (elements) and their ratios in a compound.

• For example, glucose (C6H12O6) has a specific composition of carbon, hydrogen, and oxygen.

• Inorganic compounds like NaCl (sodium chloride) consist of sodium and chlorine in a 1:1 ratio.

Phosphorous analysis involves determining the concentration of phosphorous in a sample using various analytical techniques.

• Phosphorous analysis is important in environmental monitoring to assess pollution levels.

• Common methods for phosphorous analysis include colorimetric assays, spectrophotometry, and ion chromatography.

• Phosphorous can exist in different forms such as orthophosphate, polyphosphate, and organic phosphorous compounds.

• Accurate phosphorous analysis is crucial in...read more