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‘Crystalline solids are anisotropic in nature’. What does this statement mean?Marks:1
This statement means that some of the physical properties of crystalline solids such as electrical resistance or refractive index show different values when measured along different directions in the same crystals.
Express the relation between conductivity and molar conductivity of a solution held in a cell.Marks:1
The molar conductivity of a solution at a given concentration is related to conductivity of that solution, by the following relation –
where m is molar conductivity and is the conductivity of the solution.
Electrophoresis is the phenomenon of movement of colloidal particles under the applied electric potential.
Draw the structure of XeF2 molecule.Marks:1
XeF2 is a linear molecule and can be drawn as follows:
Write the IUPAC name of the following compound:
The IUPAC name of the given compound is 2, 2-dimethylbromopropane.
Draw the structure of 3-methylbutanal.
Arrange the following compounds in an increasing order of their solubility in water:
C6H5NH2, (C2H5)2NH, C2H5NH2Marks:1
The solubility order of the given amines is as follows:
C6H5NH2 < (C2H5)2NH < C2H5NH2
What are biodegradable polymers?Marks:1
A polymer that can be decomposed by bacteria (micro-organism) is called a biodegradable polymer.
For example: poly--hydroxybutyrate-co--hydroxyvalerate (PHBV) is biodegradable aliphatic polyester.
The chemistry of corrosion of iron is essentially an electrochemical phenomenon. Explain the reactions occurring during the corrosion of iron in the atmosphere.Marks:2
The process of corrosion is a redox reaction and it involves simultaneous oxidation and reduction reactions. It can therefore be referred as an electrochemical phenomenon.
In the process of corrosion, due to the presence of air and moisture, oxidation takes place at a particular spot of an object made of iron. That spot behaves as the anode. The reaction at the anode can be written as follows:
Anodic reaction: Fe(s) Fe2+(aq) + 2e-
Electrons released at the anodic spot move through the metallic object and go to another spot of the object. There in the presence of H+ ions, the electrons reduce molecular oxygen. This spot behaves as the cathode. These H+ ions come either from H2CO3, which is formed due to the dissolution of carbon dioxide from air into water, or from the dissolution of other acidic oxides from the atmosphere in water.
The reaction taking place at cathode is written as follows:
Cathodic reaction: O2(g) + 2H+(aq) + 2e- 2H2O(l)
Thus, the overall reaction is:
Fe(s) + O2(g) + 2H+(aq) Fe2+(aq) + 2H2O(l)
Also, ferrous ions are further oxidised by atmospheric oxygen to ferric ions. These ferric ions combine with moisture present in the surroundings to form hydrated ferric oxide (Fe2O3.xH2O) i.e., rust.
Determine the values of equilibrium constant (KC) and G° for the following reaction:
Ni(s) + 2Ag+(aq) Ni2+(aq) + 2Ag(s), E° = 1.05V
(1F = 96500 C.mol-1)Marks:2