Chemistry · Science General

Separation Techniques

842 Questions

Separation techniques involve physical methods to isolate mixtures, including distillation, filtration, and crystallization. Competitive exams frequently test these foundational concepts. Review the exact processes to enhance problem solving speed.

Distillation and evaporationCrystallization processFiltration methodsSeparating dissolved solidsChromatography and mass techniques

Separation Techniques Questions

Multiple choice botany biotechnology: principles and processes downstream processing biotechnology biotechnology and its application

Which of the following is not component of downstream processing ____________.

  1. Expression

  2. Separation

  3. Purification

  4. Presentation
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Downstream processing involves the recovery, purification, and packaging of the product after fermentation. Expression is the process that occurs during the upstream phase (fermentation/cultivation).

Multiple choice botany biotechnology: principles and processes downstream processing biotechnology biotechnology and its application

Which of the following is not a component of downstreaming processing?

  1. Separation

  2. Purification

  3. Preservation

  4. Expression
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
A widely recognized heuristic for categorizing downstream processing operations divides them into four groups which are applied in order to bring a product from its natural state as a component of a tissue, cell or fermentation broth through progressive improvements in purity and concentration.

Removal of insolubles is the first step and involves the capture of the product as a solute in a particulate-free liquid, for example the separation of cells, cell debris or other particulate matter from fermentation broth containing an antibiotic. Typical operations to achieve this are filtration, centrifugation, sedimentation, precipitation, flocculation, electro-precipitation, and gravity settling. Additional operations such as grinding, homogenization, or leaching, required to recover products from solid sources such as plant and animal tissues, are usually included in this group.

Product isolation is the removal of those components whose properties vary considerably from that of the desired product. For most products, water is the chief impurity and isolation steps are designed to remove most of it, reducing the volume of material to be handled and concentrating the product. Solvent extraction, adsorption, ultrafiltration, and precipitation are some of the unit operations involved.

Product purification is done to separate those contaminants that resemble the product very closely in physical and chemical properties. Consequently steps in this stage are expensive to carry out and require sensitive and sophisticated equipment. This stage contributes a significant fraction of the entire downstream processing expenditure. Examples of operations include affinity, size exclusion, reversed phase chromatography, ion-exchange chromatography, crystallization and fractional precipitation.

Product polishing describes the final processing steps which end with packaging of the product in a form that is stable, easily transportable and convenient. Crystallization, desiccation, lyophilization and spray drying are typical unit operations. Depending on the product and its intended use, polishing may also include operations to sterilize the product and remove or deactivate trace contaminants which might compromise product safety. Such operations might include the removal of viruses or depyrogenation.

So the correct option is 'Expression'.
Multiple choice spectrophotometer, colorimeter and biosensor biochemical techniques bio-chemistry

Isopycnic or equal density centrifugation is achieved in

  1. Buoyant density centrifugation

  2. Density gradient centrifugation

  3. Electrophoresis

  4. Differential centrifugation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Isopycnic centrifugation, also known as equilibrium density gradient centrifugation, separates particles based solely on their buoyant density rather than their size or shape.

Multiple choice spectrophotometer, colorimeter and biosensor biochemical techniques bio-chemistry

In which of the following types of centrifugation, the components of separation are based on size, shape and density?

  1. Differential centrifugation

  2. Zonal centrifugation

  3. Density gradient centrifugation

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In differential centrifugation particles of different density, size and shape in a suspension sediment at different rates, with the larger and denser particles sedimenting faster. These sedimentation rates can be increased by using centrifugal force. Thus the correct answer is 'Differential centrifugation'.

Multiple choice spectrophotometer, colorimeter and biosensor biochemical techniques bio-chemistry

Which technique is used in separating proteins from other fractions?

  1. Chromatography

  2. Autoradiography

  3. Electrophoresis

  4. Ultracentrifugation
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Ultracentrifugation is a primary technique used to isolate cellular organelles and protein fractions based on their sedimentation rates, which are determined by size and density.

Multiple choice spectrophotometer, colorimeter and biosensor biochemical techniques bio-chemistry

Pure fractions of cellular components are isolated by

  1. Chromatography.

  2. Differential centrifugation.

  3. Scanning electron microscopy.

  4. X-ray diffraction.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Differential centrifugation is the standard method for separating cellular components based on their size and density by applying increasing centrifugal forces.

Multiple choice spectrophotometer, colorimeter and biosensor biochemical techniques bio-chemistry

Heavier and lighter isotropic forms of an element can be separated by which technique?

  1. Electrophoresis

  2. Density gradient centrifugation

  3. Buoyant density centrifugatio

  4. Chromatography
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Buoyant density centrifugation 

It is also called isopycnie centrifugation or equilibrium density - gradient centrifugation which uses the concept of Buoyancy to separate molecules in solutions by their difference in density.

Multiple choice chemistry pure substances and mixtures: separation of mixtures difference between mixtures and compounds pure substance and mixtures types of pure substances

Among the following, which is\are the difference between compound and mixture?

  1. The constituents of a compound can be separated only by chemical methods.

    The constituents of a mixture can be separated easily by physical methods.

  2. Compounds are pure substances.

    Mixtures are impure substances.

  3. The constituents of a compound are present in a fixed ratio.

    The constituents of a mixture are present in varying ratios.

  4. All of above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Compounds are pure substances whereas mixture are impure substances. The constituents of a compound can be separated only by chemical methods and that of a mixture can be separated easily by physical methods. The constituents of a compound are present in a fixed ratio.The constituents of a mixture are present in varying ratios.

Multiple choice distinction between pairs of amines organic compounds containing nitrogen organic compounds with functional group containing nitrogen chemistry

Primary, secondary, tertiary amines can be separated by the following except: 

  1. Fractional distillation

  2. Fractional method using diethyl oxalate
  3. Hinsberg's method using $\displaystyle { C } _{ 6 }{ H } _{ 5 }{ SO } _{ 2 }Cl$

  4. Selective crystallisation
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Separation of $1^o,\, 2^o$ and $3^o$ amines:

$1^o,\, 2^o$ and $3^o$ amines + $R _4NX \xrightarrow{distillation}$ Mixture of $1^o,\, 2^o,\, 3^o$ amine
Mixture  of $1^o,\, 2^o,\, 3^o$ amine can be separated by following methods.
(i) Fractional distillation: The mixture of amines may be fractional distillation because their boiling points are quite different. It is used in industry.

(ii) Hinsberg method: In this method mixture of amines is seperated by using benzene sulphonyl chloride (Hinsberg's reagent).
$C _6H _5SO _2Cl+1^o\,amine \to Product \xrightarrow{KOH} dissolve$
$C _6H _5SO _2Cl+2^o\,amine \to Product \xrightarrow{KOH} insoluble$
$3^o$ amine does not react with benzene sulphonyl chloride.

(iii) Hofman method: In this method mixture of amines is separated by using ethyl oxalate.
$1^o$ amine + ethyl oxalate $\to$ solid product
$2^o$ amine + ethyl oxalate $\to$ liquid product
$3^o$ amine + ethyl oxalate $\to$ No reaction

Multiple choice distinction between pairs of amines organic compounds containing nitrogen organic compounds with functional group containing nitrogen chemistry

Mixture of $1^0, 2^0 $ and $3^0$ amines can be separated by :

  1. Hinsberg's method

  2. Hofmann's isocyanide test

  3. Fractional distillation
  4. $NaNO _2/ HCl$
Reveal answer Fill a bubble to check yourself
A,B,C,D Correct answer
Explanation
All the given methods can be used for the separation of amines.

(A) Hinsberg reaction is a chemical test for the detection of amines. A primary amine will form a soluble sulfonamide salt which precipitates after addition of diluted hydrochloric acid. A secondary amine in the same reaction will directly form an insoluble sulfonamide. A tertiary amine will not react with the sulfonamide but is insoluble. After adding dilute acid this insoluble amine is converted to a soluble ammonium salt. 

(B) In Hofmann's isocyanide test the mixture of three amines is treated with diethyl oxalate. The primary amine forms a solid oxamide, a secondary amine gives a liquid oxamic ester while tertiary amine does not react.

(C) In fractional distillation primary amine is recovered when solid oxamide is heated with caustic potash solution and collected as distillate on distilling the reaction mixture. The liquid is subjected to fractional distillation when tertiary amine distils over. The remaining liquid is distilled with KOH to recover secondary amine.

(D) Nitrosation of Amines can also be used for separation as primary amine with $NaNO _2 + HCl$ forms $RN _2$, secondary amine forms $R _2N _2O$ and tertiary amine forms $R _3NO$ which decomposes into $NR _3$.