Engineering Chemistry Multiple Choice Questions on “Chromatography”.
1. Chromatography is the process for identification, purification and separation of components of a mixture on the basis of ____________
a) Difference in their boiling point
b) Difference in their melting point
c) Difference in their affinity for mobile and stationary phase
d) Difference in their solubility
Answer: c
Clarification: Chromatography is the process for identification, purification and separation of components of a mixture on the basis of difference in their affinity for mobile and stationary phases. The mixture is dissolved in a fluid called the mobile phase, which carries it through a structure holding another material called the stationary phase.
2. Chromatography involves two mutually ____________
a) Immiscible phases
b) Miscible phases
c) Soluble phases
d) None of the mentioned
Answer: a
Clarification: Chromatography involves two mutually immiscible phases (stationary and mobile phases). The mixture is dissolved in a fluid called the mobile phase, which carries it through a structure holding another material called the stationary phase.
3. There is no need of support if packed into a column when the stationary phase is ____________
a) Gas
b) Liquid
c) Solid
d) None of the mentioned
Answer: c
Clarification: If the stationary phase is solid, there is no need of support if packed into a column. In solid phase, all the molecules are already in closed packing.
4. Which of the following is not a stationary phase?
a) Liquid-liquid chromatography
b) Gas-liquid chromatography
c) Gas-solid chromatography
d) Solid-solid chromatography
Answer: d
Clarification: Solid-solid chromatography is not a stationary phase because solid-solid phase cannot provide any fluidity.
5. Liquid chromatography is a technique for separating ____________
a) Ions that are not dissolved in a solvent
b) Ions that are dissolved in a solvent
c) Ions that are dissolved in a solute
d) All of the mentioned
Answer: b
Clarification: Liquid chromatography is a technique for separating ions that are dissolved in a solvent. Solute is the material which is dissolved and solvent is the solution in which it is dissolved.
6. In exclusion chromatography, solute molecules are separated based on ____________
a) Molecular geometry and size
b) Molecular composition
c) Molecular phase
d) Molecular formula
Answer: a
Clarification: In exclusion chromatography, solute molecules are separated based on molecular geometry and size. These two physical characteristics have a significance role in exclusion chromatography.
7. The gas-solid chromatography is ______________ chromatography as per basic principle involved.
a) Exclusion
b) Ion-exchange
c) Adsorption
d) Absorption
Answer: c
Clarification: The gas-solid chromatography is adsorption chromatography as per basic principle involved as the gas molecules are adsorbed on the solid surface.
8. A proper solvent that is passed through the column for elution so that separated components can be collected is called ____________
a) Adsorbent
b) Buffer solution
c) Mobile phase
d) None of the mentioned
Answer: b
Clarification: A proper solvent that is passed through the column for elution so that separated components can be collected is called buffer solution. The eluate is the mobile phase leaving the column. The eluent is the solvent that carries the analyte.
9. The relative solubility of solute in both the phases determines the ____________
a) Rate of movement of solvent
b) Rate of disappearance of solvent
c) Rate of movement of solute
d) Rate of disappearance of solute
Answer: c
Clarification: The relative solubility of solute in both the phases determines the rate of movement of solute as solute is added to the solution.
10. If the mobile phase is gas, movement of solute is determined by its ____________
a) Boiling point
b) Melting point
c) Solubility
d) Volatility
Answer: d
Clarification: If the mobile phase is gas, movement of solute is determined by its volatility because gas is always measured as volatility not as solubility or melting point or boiling point.