Question:
Draw the structure of Al_4C_3.
Question:
Ca_2C reacts with water to give Ca(OH)_2. Write out another product.
Solutioon:
C_2H_2
Question:
(a) Draw the anion of a cryolite crystal.
(b) What is the use of this crystal?
Question:
AlF_3 is added to the molten aluminum to decrease the solubility of the latter. What is this phenomenon called?
Solution:
Common ion effect
Question:
AlCl_3 is an active ingredient of common antiperspirant. Explain why excess use of it is harmful to human skins.
Solution:
AlCl_3 (aq) + 3H_2O (l) + heat \to Al(OH)_3 + 3HCl
As a result, acidic HCl will corrode your skin pore.
Quesion:
AlH_3 is a covalent crystal. Discuss how it can form an adduct.
Solution:
It is a Lewis acid. It reacts with a Lewis base to form an adduct:
AlH_3 + LiH \to LiAlH_4
Question:
Al_2Cl_6 is a solid. Explain why it sublimes upon heating.
Solution:
The dative bondings in Al_2Cl_6 (s) are rather weak. Upon heating, it decomposes into AlCl_3 (g)
Question:
Draw the structure of Bauxite.
Question:
Suggest 2 impurities commonly found in Aluminum ores.
Solution:
Fe_2O_3, SiO_2
Question:
Silicates can be corroded by moisture. Explain briefly.
Solution:
Na_2SiO3 + CO_2 + H_2O \to NaHCO_3 + NaHSiO_3
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