Question

Which of the following is not an ore of aluminium?
A: Bauxite
B: Cryolite
C: Kernite
D: Corundum

Answer 1

Hint: An ore is a naturally occurring substance through which valuable minerals can be extracted mostly metals are extracted. Ores are found in earth’s crust then undergo under different processes so that we can get pure metal.

Complete step by step answer:
Metals like aluminium can be extracted from various types of ores which can give considerable amounts of aluminium on refining them through some metallurgical process.
Analyzing the given options
Chemical formula of Bauxite is $A{l_2}{H_2}{O_4}$ and it is an aluminium rich ore so it is definitely a rich source of aluminium to be extracted.
Chemical formula of cryolite is $N{a_3}Al{F_6}$ which is also an aluminium rich ore.
Chemical formula of Kernite is $N{a_2}{B_4}{O_6}$ .
Chemical formula of corundum is $A{l_2}{O_3}$which is an oxide of aluminium and definitely an ore of aluminium.

Hence the answer is option C that is Kernite which is not an ore of aluminium instead it is an ore of boron.

Additional information: Metallurgy is the series of processes to get pure metal from different ores. This process involves various steps to be followed which are given below
1. Getting an ore from natural resources by various methods such as mining.
2. Crushing and grinding of that ore.
3. Concentration of ore by various methods such as gravity separation, magnetic separation, leaching, froth floatation.
4. Roasting and calcination (depending on the requirement)
5. Reduction (Reduction by carbon, electrolysis, heat alone, carbon monoxide)
6. Refining by appropriate method some methods are given such as distillation, liquification, oxidation and electrorefining.
After all these processes are done according to the ore or properties of elements we get a pure metal extracted from its ore.
Aluminium is a silvery-white lightweight metal which is soft and malleable. It is a light weight substitute for steel hence used in manufacturing of planes or materials in which we need high strength to weight ratio.

Note: Kernite is the ore of boron not aluminium. Ores are generally oxides, sulfides, silicates or noble metals like gold. You have to remember all the names of ores and their chemical formula.