Page 356 - General Knowledge

GENERAL KNOWLEDGE 2019

 Anode reaction:
-
+
-
Pb(s) + HSO 4 (aq)  PbSO 4(s) + H (aq) + 2e
 Cathode reaction:
+
-
-
PbO 2(s) + 3H (aq) + HSO 4 (aq) + 2e  PbSO 4(s) + 2H 2O(m)
Electrolysis
 A galvanic cell produces current from a spontaneous oxidation-reaction.
 An electrolytic cell uses electrical energy to drive nonspontaneous oxidation-reduction
reactions.
 Electrolysis involves forcing a current through a cell to produce a chemical change, which
has a negative cell potential.
 Three types of reactions are possible in electrolytic cells when a sufficient voltage is applied:

 Solute ions or molecules may be oxidized or reduced;
 The solvent can be oxidized or reduced;
 Metal electrode that forms the anode can be oxidized.

6. INORGANIC CHEMISTRY
 Inorganic chemistry is of fundamental importance not only as a basic science but also as
one of the most useful sources for modern technologies.
 Elementary substances and solid-state inorganic compounds are widely used in the core of
information, communication, automotive, aviation and space industries as well as in
traditional ones.
 Inorganic compounds are also indispensable in the frontier chemistry of organic synthesis
using metal complexes, homogeneous catalysis, bioinorganic functions, etc.
Modern Periodic Law
 Properties of elements are the periodic function to their atomic numbers

 The periodicity in properties is due to repetition of similar outer shell electronic configuration
at a certain regular intervals.
 In modern periodic table is based on modern periodic law in which elements are arranged in
increasing order of their atomic numbers.
 In the modern periodic table, the elements are arranged in rows and columns. These rows
and columns are known as periods and groups respectively.
 The table consists of 7 periods and 18 groups.
 Period indicates the value of ‗n‘ for the outermost or valence shell.
 Same number of electrons are present in the outer orbitals.

Types of Ores
 Native Ores: These ores contain the metal in Free State. These are actually formed in the
company of rock or alluvial impurities like clay, sand etc.
 Oxidised Ores: These ores consist of oxides or oxysalts and silicate of metal. Important
oxide ore includes, Fe 2O 3, Al 2O 3, 2H 2O etc.
 Sulphurised Ores: These ores consist of sulfides of metals like iron, lead, mercury etc.
 Halide ores: Metallic halides are very few in nature.

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