New Concepts/Shortcuts 21

Question 1

what are activators in enzyme reactions?

what do they do and give on eg of them?

Answer 1

Activators are generally metal ions such as Na+ , Mn2+ , Co2+ , Cu2+ etc. These metal ions, when weakly bonded to enzyme molecules, increase their catalytic activity. Amylase in presence of sodium chloride i.e., Na+ ions are catalytically very active

Question 2

What’s used the in contact proces and whats the contact process?

Answer 2

Question 3

whats the colloid particle size range

Answer 3

Colloidal particles are larger than simple molecules but small enough to remain suspended. Their range of diameters is between 1 and 1000 nm (10–9 to 10–6 m).

Question 4

why does the colloidal particle have an enormous surface area per unit mass?

Answer 4

Colloidal particles have an enormous surface area per unit mass as
a result of their small size

Question 5

whats kraft temperature and critical micelle concentration?

Answer 5

The formation of micelles takes place only above a particular temperature called Kraft temperature (Tk) and above a particular concentration called critical micelle concentration (CMC)

Question 6

what happens on dilution of micelle solution

Answer 6

On dilution, these colloids revert back to individual ions

Question 7

whats associated colloids?

Answer 7

There are some substances which at low concentrations behave as normal strong electrolytes, but at higher concentrations exhibit colloidal behaviour due to the formation of aggregates. The aggregated particles thus formed are called micelles. These are also known as associated colloids

Question 8

why does the Tyndall effect occur?

Answer 8

The Tyndall effect is due to the fact that colloidal particles scatter light in all directions in space. This scattering of light illuminates the path of the beam in the colloidal dispersion

Question 9

explain the cleansing action of soaps

Answer 9

the polar groups can interact with water, the oil droplet surrounded by stearate ions is now pulled in water and removed from the dirty surface. Thus soap helps in emulsification and washing away oils and fats. The negatively charged sheath around the globules prevents them from coming together and forming aggregates.

Question 10

how are colloidal dispersions made from chemical reactions?

Answer 10

Question 11

what happens in bredig’s arc method?

Answer 11

this process involves dispersion as well as condensation. Colloidal sols of metals such as gold, silver, platinum, etc., can be prepared by this method. In this method, electric arc is struck between electrodes of the metal immersed in the dispersion medium.The intense heat produced vapourises the metal, which then condenses to form particles of colloidal size.

Question 12

whats peptization?!

Answer 12

Peptization may be defined as the process of converting a precipitate into colloidal sol by
shaking it with dispersion medium in the presence of a small amount of electrolyte. The electrolyte used for this purpose is called peptizing agent

Question 13

What’s the concept of dialysis?!

Answer 13

Since particles (ions or smaller molecules) in a true solution can pass through an animal
membrane (bladder) or parchment paper or cellophane sheet but not the colloidal particles,
the membrane can be used for dialysis. The apparatus used for this purpose is called a dialyzer. A bag of suitable membranes containing the colloidal solution is suspended in a vessel through which fresh water is continuously flowing (Fig. 5.9). The molecules and ions diffuse through the membrane into the outer water and the pure colloidal solution is left behind.

Question 14

whats Ultrafiltration?

Answer 14

Ultrafiltration is the process of separating the colloidal particles from the solvent and soluble solutes present in the colloidal solution by specially prepared filters, which are permeable to all substances except the colloidal particles

Question 15

Whats a collodion solution?

Answer 15

the pores of filter paper can be reduced in size by impregnating it with collodion solution to stop the flow of colloidal particles. The usual collodion is a 4% solution of nitrocellulose in a
mixture of alcohol and ether

Question 16

how can we make an ultra filter paper!?

Answer 16

An ultra-filter paper may be prepared by soaking the filter paper in a collodion solution, hardening by formaldehyde and then finally drying it.

Question 17

why does ultra microscope not provide any information about the size and shape of colloidal particles?

Answer 17

Ultramicroscope does not render the actual colloidal particles visible but only observe the light scattered by them. Thus, ultramicroscope does not provide any information about the size and shape of colloidal particles.

Question 18

how can a mixture of milk and water appear blue?

Answer 18

a mixture of milk and water appears blue when viewed by the reflected light and red when viewed by the transmitted light

Question 19

how and why does the color of gold sol change?

Answer 19

The finest gold sol is red in color; as the size of particles increases, it appears purple, then blue, and finally golden.

Question 20

brownian motion is dependent on?

Answer 20

This motion is independent of the nature of the colloid but depends on the size of the particles and viscosity of the solution. Smaller the size and lesser the viscosity, faster is the motion.

Question 21

What’s the explanation of brownian motion?

Answer 21

The Brownian movement has been explained to be due to the unbalanced bombardment of the particles by the molecules of the dispersion medium. The Brownian movement has a stirring effect which does not permit the particles to settle and thus, is responsible for the stability of sols.

Question 22

what provides stabilty to collloidal solution?

Question 23

conformations of butane

Answer 23

Question 24

stability order of the butane conformations

Answer 24

Question 25

how to use the sandwich theorem

Answer 25

Question 26

Answer 26

Question 27

Answer 27

Question 28

Answer 28

Question 29

Answer 29

Question 29

whats contrapositive,inverse and converse statements

Answer 29

Question 30

whats the dimensions of Coeff of viscosity?

Answer 30

Question 31

eg of pesticides

Answer 31

Organophosphates
Dieldrin
DDT

Question 32

eg of herbicides

Answer 32

Sodium arsenite

Question 33

techniques is used to spot components of a mixture separated on thin layer chromatographic plate?

Answer 33

I2 (Solid)
U.V. Light
Spraying of an appropriate reagent

Question 34

whats the purpose of the Visualisation agent as a component of mobile
phase in chromatography

Answer 34

The function of the mobile phase is to carry the components present on TLC

Question 35

which ligands/compounds show synergic bonding?

Answer 35

CO ligand shows synergic bonding, so all complexes can show synergic bonding

Question 35

what are the new materials that have the potential to provide materials that is tougher than steel/life than aluminum and have more conductive properties than copper

Answer 35

copper nanotubes

Question 36

What’s a long-range order?

Answer 36

a long-range order means that there is a regular pattern of arrangement of particles which repeated itself periodically over the entire crystal

Question 37

whats a short-range order

Answer 37

a regular and periodically repeating pattern is observes over short distances only

Question 38

are amorphous solids viscous liquids?

Answer 38

amorphous solids have the same structural features as liquids and are conveniently regarded as extremely viscous liquids