Free Master of Chemistry: Industrial Chemistry Questions and Answers — Questions and Answers

Question 1: Which way of operation is not appropriate for a chemical or biochemical plant?

Discontinuous (Correct answer)
Semi-continuous
Batch-wise
aContinuous

Correct answer: Discontinuous

Chemical and biochemical plants typically operate in well-defined modes such as batch-wise, semi-continuous, or continuous, each suited for different production scales and product types. While batch-wise operation is a type of discontinuous process, the term 'discontinuous' on its own might imply an unstructured or inefficient stop-and-start operation that lacks the controlled nature of a batch process. Such an unorganized 'discontinuous' operation would generally not be appropriate for efficient plant functioning.

Question 2: When is a separation step in a manufacturing process not necessary?

When the reaction is reversible
When the byproducts are in form of gases
When there is a complete conversion (Correct answer)
When there is a decomposition reaction

Correct answer: When there is a complete conversion

A separation step in a manufacturing process is typically necessary to isolate the desired product from unreacted starting materials, catalysts, and byproducts. However, if a reaction achieves complete conversion of reactants to the desired product with no significant byproducts, then the product stream would be essentially pure, and a dedicated separation step might not be required. This ideal scenario eliminates the need for purification.

Question 3: Why is there a need for separation if just 5% of ethylene is transformed to ethylene glycol?

To start an intermediate reaction
To recover the unreacted Ethylene Glycol (Correct answer)
To remove the ethylene glycol formed
To feed more reactant to the reacting mixture

Correct answer: To recover the unreacted Ethylene Glycol

If only 5% of ethylene is transformed into ethylene glycol, it means 95% of the initial ethylene remains unreacted. For the process to be economically viable and environmentally responsible, this large quantity of unreacted ethylene must be separated from the product (ethylene glycol) and subsequently recovered. The recovered unreacted ethylene can then be recycled back into the reactor, significantly improving the overall process efficiency and reducing raw material costs.

Question 4: Will the aforementioned reaction call for a separation procedure?

Yes
No (Correct answer)

Correct answer: No

Based on the premise from the previous question (Q24), where only 5% of ethylene is converted to ethylene glycol, a separation procedure is indeed necessary. The unreacted 95% of ethylene must be separated from the 5% product (ethylene glycol) for product purification and reactant recycling. Therefore, the statement that a separation procedure is not called for is inconsistent with standard chemical engineering principles for low-conversion reactions.

Question 5: How is the diethyl ether removed from ethylene during the production of ethanol?

Light-ends tower (Correct answer)
Directly removed
Crude distillation column
Low pressure flash drum

Correct answer: Light-ends tower

In industrial ethanol production, especially via the hydration of ethylene, diethyl ether is a common byproduct. A light-ends tower, which is a type of distillation column, is specifically used to separate more volatile components like diethyl ether from the desired ethanol product. This separation leverages differences in boiling points to ensure the purity of the final ethanol stream.

Question 6: Feed mixtures made of non-renewable resources like coal and petroleum are needed for chemical processes. What are non-renewable sources replaced by?

Biodiesel
Sunlight
Microorganisms
Biomass (Correct answer)

Correct answer: Biomass

To achieve sustainability in chemical processes, there is a growing shift away from non-renewable resources such as coal and petroleum. Biomass, which includes organic matter from plants and animals, serves as a renewable and abundant alternative feedstock. It can be converted into a wide range of chemicals and fuels, reducing reliance on fossil resources and promoting a more circular economy.

Question 7: Which of the following is a requirement for a biochemical plant to operate?

Chemical catalyst
Metallic catalyst
Non-pathologic state of the organism (Correct answer)
Elevated temperature

Correct answer: Non-pathologic state of the organism

Biochemical plants rely on living organisms, such as bacteria or fungi, to carry out desired reactions. A fundamental requirement for efficient operation is maintaining the organism in a non-pathologic state, meaning it must be healthy and free from disease or contamination. Healthy organisms ensure optimal metabolic activity, leading to efficient product formation and high yields.

Question 8: What changes the physiological circumstances in a biochemical plant?

The ambient conditions
The micro-organism (Correct answer)
State of the products
The reaction

Correct answer: The micro-organism

In a biochemical plant, the microorganism itself is the primary driver of the biochemical reactions and significantly alters the physiological environment. Its metabolic processes consume nutrients, produce metabolites, and influence factors like pH, temperature, and oxygen levels within the bioreactor. Therefore, the specific microorganism and its activity are central to defining the physiological circumstances.

Question 9: How else could citric acid be made besides from lemons?

Anaerobic fermentation of glucose
Aerobic fermentation of starch (Correct answer)
Anaerobic fermentation of starch
Aerobic fermentation of glucose

Correct answer: Aerobic fermentation of starch

Industrially, citric acid is predominantly produced through aerobic fermentation, primarily using the fungus Aspergillus niger. While glucose is a common substrate, starch can also be utilized as a carbon source after being hydrolyzed into glucose. The process requires an aerobic (oxygen-rich) environment for the fungus to efficiently metabolize the substrate and synthesize citric acid.

Question 10: Which of the following separation methods DOES NOT take place during the production of citric acid?

Distillation (Correct answer)
Crystallization
Ion-exchange
Ultrafiltration

Correct answer: Distillation

The production of citric acid typically involves several purification steps after fermentation, such as ultrafiltration to remove biomass, ion-exchange for impurity removal, and crystallization to isolate the pure product. Distillation, which separates components based on volatility differences, is not employed for citric acid purification. Citric acid is a non-volatile solid that would decompose at the high temperatures required for distillation.

Question 11: What method of separation is employed when a chemical reaction aids in separation during a separation operation?

Fractional crystallization
Reactive distillation (Correct answer)
Fractional distillation
Distillation

Correct answer: Reactive distillation

Reactive distillation is a specialized separation method that integrates a chemical reaction and distillation into a single unit operation. In this process, the chemical reaction occurs simultaneously with the separation of products and reactants by distillation. This combination can enhance reaction conversion, improve selectivity, and reduce overall process costs by continuously removing products or reactants.

Question 12: Of the following machines, which one doesn't require a chemical separation method?

Water cooler
The washing machine
Refrigerator
Coffee machine (Correct answer)

Correct answer: Coffee machine

A coffee machine primarily uses physical filtration to separate solid coffee grounds from the brewed liquid. Unlike a washing machine, where detergents chemically interact with dirt to facilitate its separation from fabric, the coffee machine's core separation process does not rely on chemical reactions or chemical property changes. Water coolers and refrigerators do not perform separation as their primary function.

Question 13: Which of the following is NOT a separation procedure that is important?

Increases the speed of the reaction (Correct answer)
Reduces the probability of side reactions
Reduces the risk of explosion
Reduces the operating cost

Correct answer: Increases the speed of the reaction

Separation procedures are vital in chemical processes for purifying products, recycling unreacted materials, and removing impurities to prevent side reactions or safety hazards. However, the primary role of separation is not to increase the speed of a chemical reaction. Reaction kinetics are typically influenced by factors such as temperature, pressure, catalyst presence, and reactant concentrations.

Question 14: Of the following, which is NOT a representation of a chemical process?

Semantic diagram
Flow chart (Correct answer)
Process-flow diagram
Block flow diagram

Correct answer: Flow chart

In chemical engineering, specific and standardized diagrams are used to represent chemical processes, such as Block Flow Diagrams (BFD) and Process Flow Diagrams (PFD). While a 'flow chart' is a general diagram showing steps in a process, it is a broad term and not a specific, standardized type of chemical process representation in the same way BFDs or PFDs are.

Question 15: Which of the following separation methods is based on volatility differences?

Fractional crystallization
Magnetic separation
Crystallization
Distillation (Correct answer)

Correct answer: Distillation

Distillation is a fundamental separation technique that exploits differences in the volatility of components within a liquid mixture. By heating the mixture, the more volatile components preferentially vaporize, and these vapors are then condensed and collected. This difference in boiling points allows for the effective separation and purification of substances.

Question 16: Which differences are exploited by crystallization?

Bubble point
Melting point (Correct answer)
Boiling point
Specific heat

Correct answer: Melting point

Crystallization is a separation method that primarily exploits differences in the solubility of components in a solvent, often influenced by temperature. While solubility is the direct property, the ability of a substance to form a stable crystalline structure and its distinct melting point are intrinsically linked to its purification by crystallization. This process aims to isolate a pure component based on its ability to solidify from a solution or melt.

Free Master of Chemistry: Industrial Chemistry Questions and Answers

Which way of operation is not appropriate for a chemical or biochemical plant?