Identify the term or substance based on the descriptions given below:
i. Ice like crystals formed on cooling an organic acid sufficiently.
ii. Hydrocarbon containing a triple bond used for welding purposes.
iii. The property by virtue of which the compound has the same molecular formula
but different structural formulae.
iv. The compound formed where two alkyl groups are linked by group.

Give a balanced chemical equation for each of the following:
i. Preparation of ethane from Sodium propionate
ii. Action of alcoholic ``\ce{KOH}`` on bromethane.

Name the following:
i. The process of coating of iron with zinc.
ii. An alloy of lead and tin that is used in electrical circuits.
iii. An ore of zinc containing its sulphide.
iv. A metal oxide that can be reduced by hydrogen.

Answer the following questions with respect to the electrolytic process in the extraction
of aluminum:
i. Identify the components of the electrolyte other than pure alumina and the role
played by each.
ii. Explain why powdered coke is sprinkled over the electrolytic mixture.

Complete the following by selecting the correct option from the choices given:
i. The metal which does not react with water or dilute ``\ce{H2SO4}`` but reacts with
concentrated ``\ce{H2SO4}`` is _________. (``\ce{Al/Cu/Zn/Fe}``)
ii. The metal whose oxide, which is amphoteric, is reduced to metal by carbon
reduction ____________. (``\ce{``Fe/Mg/Pb/Al}``)
iii. The divalent metal whose oxide is reduced to metal by electrolysis of its fused salt
is __________. (``\ce{``Al/Na/Mg/K}``)