Question

Difference in density is the basis of:
A. Ultrafiltration
B. Molecular sieving
C. Gravity separation
D. Molecular attraction
E. Atomic absorption

Answer 1

Hint: After the extraction of an organic compound from a crude origin or prepared in the laboratory, purification is essential. Different techniques are utilised for the cleansing of organic compounds established on the characteristics of the compound and the contaminant present in it.

Complete Step by Step Solution:
After the purification, the purity of a compound is verified by specifying its melting or boiling point. Maximum pure compounds maintain sharp melting points and boiling points.

We have to find out which of the given options is based on the difference in the density.
A. Ultrafiltration
It is a type of membrane filtration process in which forces like pressure or concentration gradients are useful for the separation. It utilises a semipermeable membrane. Suspended solids and solutes of high molecular weight do not pass through the membrane, and water and low molecular weight solutes pass through the membrane in the filtrate. It is employed in industry and analysis and purification of macromolecular solutions. So, this method is based on the differences in molecular weight.
So, A is incorrect.

B. Molecular sieving
A molecular sieve is a material with very tiny holes of uniform dimensions. These holes are identical in size thus big molecules cannot pass or be adsorbed, while smaller molecules can pass through them. This technique is based on molecular size.
So, B is incorrect.

C. Gravity separation
Gravity separation is an industrial technique of singling out two components, either a suspension or a mixture based on the difference in specific weights or densities. The benefits of the gravitational techniques are cost-effective and in some circumstances outstanding reduction.
So, B is correct.

D. Molecular attraction
The inclination of molecules with dissimilar electrical charges to pull each other. This technique is based on the principle that unlike charges attract each other. This is not based on the difference in density.
So, D is incorrect.

E. Atomic absorption
Atomic absorption spectroscopy and atomic emission spectroscopy are procedures for the quantitative finding of chemical elements utilising the absorption of light by free atoms in the gaseous state. The technique is utilised in analytical chemistry for specifying the concentration of a certain element in a sample to be analysed. So, it is not based on the difference in density. So, E is incorrect.
So, option C is correct.

Note: After the cleansing, the purity of a compound is proved by identifying its melting or boiling point. Maximum pure compounds maintain sharp melting points and boiling points. Recent techniques for studying the purity of organic compounds are established on specific kinds of chromatographic and spectroscopic techniques.