a.which one of pcl4 + and pcl4 - is not likely to exist?
b.what is the role of graphite in the electrometallurgy of aluminium?
c.why is copper(1) unstable in aq.solution?
d.what is the role of cryolite in electro metallurgy of aluminium?
d.The role of carbon monoxide in the refining of crude nickel?
e.what is meant by 1)peptide linkage 2)biocatalysts?
f.Most of the transition metal ions exhibit characteristic in colours in aq.solution?
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a). In PCl4-, Oxidation state of P is:
x - 4 = -1
x = +3
While in PCl4+ , oxidation state of P is:
x - 4 = +1
x= + 5
Since the most stable oxidation state of P is +5. Therefore PCl4+ exists and PCl4- does not exist.
b). Graphite rod is used as an anode and graphite line iron as cathode during the electrolysis of alumina. During the electrolysis aluminium is liberated at the cathode and oxygen at the anode. This oxygen reacts with the graphite anode to for CO and CO2 preventing the oxygen evolved from oxidizing aluminium.Thus the role of graphite in electrometallurgy of aluminium is to prevent the liberation of oxygen so that the aluminium is not oxidized by oxygen.
Graphite being cheaper is also an advantage.
C). In an aqueous medium, Cu2+ is more stable than Cu+. This is because although energy is required to remove one electron from Cu+ to Cu2+, high hydration energy of Cu2+ compensates for it. Therefore, Cu+ion in an aqueous solution is unstable. It disproportionates to give Cu2+ and Cu.
d. Cryolite improves the conductivity of cell and lowers the melting point of the mixture.
e). 1). Peptide linkage is between 2 alpha amino acids. The bond is formed by combination of amine group and carboxylic acid group eliminating water. Thus an amide bond is formed.
2).Biocatalyst is a an enzyme that catalysis biological or metabolical reactions in the body.
f).. Transition metal ions form hydrated complex with water molecules and thus exist as hydrated complex ions in water. During the formation of complex ions the d orbitals of the transition metals ions split into higher and lower energy levels. The electrons in the partially filled d orbitals of the transition ion absorb light energy and are promoted to higher energy levels and reflect light complementary to the colour of the light absorbed due to which the aqueous solution appears coloured.
x - 4 = -1
x = +3
While in PCl4+ , oxidation state of P is:
x - 4 = +1
x= + 5
Since the most stable oxidation state of P is +5. Therefore PCl4+ exists and PCl4- does not exist.
b). Graphite rod is used as an anode and graphite line iron as cathode during the electrolysis of alumina. During the electrolysis aluminium is liberated at the cathode and oxygen at the anode. This oxygen reacts with the graphite anode to for CO and CO2 preventing the oxygen evolved from oxidizing aluminium.Thus the role of graphite in electrometallurgy of aluminium is to prevent the liberation of oxygen so that the aluminium is not oxidized by oxygen.
Graphite being cheaper is also an advantage.
C). In an aqueous medium, Cu2+ is more stable than Cu+. This is because although energy is required to remove one electron from Cu+ to Cu2+, high hydration energy of Cu2+ compensates for it. Therefore, Cu+ion in an aqueous solution is unstable. It disproportionates to give Cu2+ and Cu.
d. Cryolite improves the conductivity of cell and lowers the melting point of the mixture.
e). 1). Peptide linkage is between 2 alpha amino acids. The bond is formed by combination of amine group and carboxylic acid group eliminating water. Thus an amide bond is formed.
2).Biocatalyst is a an enzyme that catalysis biological or metabolical reactions in the body.
f).. Transition metal ions form hydrated complex with water molecules and thus exist as hydrated complex ions in water. During the formation of complex ions the d orbitals of the transition metals ions split into higher and lower energy levels. The electrons in the partially filled d orbitals of the transition ion absorb light energy and are promoted to higher energy levels and reflect light complementary to the colour of the light absorbed due to which the aqueous solution appears coloured.
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