Answer:
Nature of oxides
The normal oxides \[({{M}_{2}}O)\] are
basic in nature. They form strong alkalies (hydroxides) when dissolved in
water. The basic nature increases on moving down the group.
\[{{M}_{2}}O+{{H}_{2}}O\to
2MOH\]
Besides monoxides, sodium and higher
alkali metals form peroxides and super oxides.
The peroxides \[({{M}_{2}}{{O}_{2}})\]
and superoxides \[(M{{O}_{2}})\]form hydroxides when hydrolysed with water.
\[{{M}_{2}}{{O}_{2}}+2{{H}_{2}}O\to
2MOH+{{H}_{2}}{{O}_{2}}\]
\[2M{{O}_{2}}+2{{H}_{2}}O\to
2MOH+{{H}_{2}}{{O}_{2}}+{{O}_{2}}\]
Peroxides and super oxides are
strong oxidising agents.
Nature of halides
The halides \[({{M}^{+}}{{X}^{-}})\]
are crystalline and have high melting and boiling points. The fused halides are
good conductors of electricity. All halides except \[LiF\]dissolve in water.
Halides are colourless and on heating turn yellow, blue, etc. Halides of
potassium, rubidium and caesium have a property of combining with extra halogen
atoms forming polyhalides
\[KI+{{I}_{2}}\to
K{{I}_{3}}\]
Nature of oxosalts
Alkali metals readily react with
oxy acids forming corresponding salts with evolution of hydrogen. Lithium salts
behave some what abnormally due to polarising power and lattice energy effects.
The carbonates of alkali metals
are highly stable towards heat and readily soluble in water. The stability
increases from Li to Cs as electropositive nature increases. Solutions are
alkaline in nature due to
hydrolysis
\[{{M}_{2}}C{{O}_{3}}+2{{H}_{2}}O\rightleftharpoons
2MOH+{{H}_{2}}C{{O}_{3}}\]
Nitrates of the type, MNO^ are
known. These are colourless and soluble in water and electrovalent in nature.
With the exception of\[LiN{{O}_{3}}\], the other nitrates decompose to nitrites
and oxygen.
\[2MN{{O}_{3}}\to
2MN{{O}_{2}}+{{O}_{2}}\]
\[LiN{{O}_{3}}\]on heating gives
\[N{{O}_{2}}\] and \[{{O}_{2}}\].
\[2LiN{{O}_{3}}\to
L{{i}_{2}}O+2N{{O}_{2}}+\frac{1}{2}{{O}_{2}}\]
Sulphate of the type \[{{M}_{2}}S{{O}_{4}}\]
are known. With the exception of\[L{{i}_{2}}S{{O}_{4}}\], other sulphates are
soluble in water. These are reduced by carbon oh heating.
\[{{M}_{2}}S{{O}_{4}}+4C\to
{{M}_{2}}S+4CO\]
The sulphates of alkali metals form
double sulphates with the sulphates of trivalent metals like Fe, Al, Cr, etc.
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