Explanation:
Bauxite contains SiO₂ (silica) as impurity. In the Bayer's process, powdered bauxite is treated with hot concentrated NaOH solution. Alumina dissolves forming sodium aluminate (NaAlO₂), while silica does not dissolve and is filtered off. Alternatively, silica can be removed by adding lime during refining. The purified alumina is then electrolyzed in cryolite. NaOH selectively dissolves Al₂O₃ due to its amphoteric nature.
Explanation:
In NO₂, each oxygen has valency 2; with two oxygens, total combining capacity = 4. Thus nitrogen's covalency is 4. The structure involves a coordinate bond. Oxidation state of N is +4. Valency is number of bonds formed: N forms two single bonds and one coordinate bond with O, total 4 bonds. In NO, valency is 2.
No comments yet. Be the first to start the discussion!