Acids, Bases and Salts — Chemistry STD 10 — Question

Draw electron dot structure of the following:
NaCl

The following is an extract from Metals in the Service of Man. Alexander and Street/Pelican 1976.
'Alumina (aluminium oxide) has a very high melting point of over 2000°C so that it cannot readily be liquefied. However, conversion of alumina to aluminium and oxygen by electrolysis can occur when it is dissolved in some other substance.
(a) Which solution is used to react with bauxite as a first step in obtaining pure aluminium oxide?
(b) The aluminium oxide for the electrolytic extraction of aluminium is obtained by heating aluminium hydroxide. Write the equation for this reaction.
(c) Name the element which serves both as the anode and the cathode in the extraction of aluminium.

(a) Fill in the blanks using the most appropriate words :
(i) The ore from which aluminium is extracted must first be treated with ________ so that pure aluminium oxide can be obtained.
(ii) Pure aluminium oxide is dissolved in ________ to make it a conducting solution.
(b) Write the formula of Cryolite.

Give reason for the following:
In the laboratory preparation of nitric acid, the mixture of concentrated sulphuric acid and sodium nitatre should not be heated very strongly, above 200°C

Give the equation for the reduction of Copper oxide

Why is the temperature maintained at 200°C in the above reaction?

Write the difference between with examples:
Electrolytic dissociation and ionization

A vessel contains N molecules of oxygen at a certain temperature and pressure. How many molecules of sulphur dioxide can the vessel accommodate at the same temperature and pressure?

Draw an electron dot diagram to show the formation of the following compound.
Magnesium chloride [ H=1, C=6, Mg=12, Cl=17].