Question

The most electropositive metals are isolated from their ores by
A. High temperature reduction with carbon
B. self- reduction
C. Thermal decomposition
D. Electrolysis of fused ionic salts

Answer 1

Hint: Electropositive elements are found at the left of the periodic table. The electropositive character means the ability of the element is not much in gaining electrons. The most electropositive elements include metals which consist of one or two electrons in their valence shell.

Complete answer:
The most electropositive elements are the elements that consist of only one or two electrons in their valence shell. These are highly reactive metals like, sodium, magnesium, calcium potassium, etc.
These metals are so reactive that they even react in air or moisture. As the reactivity of the metals is very high, they cannot be extracted by their oxides on reduction, or by the reduction with carbon, even by thermal decomposition as they even react with oxygen. So, a method of electrolysis is used to obtain these highly electropositive metals.
The isolation of highly reactive electropositive metals involves the electrolysis of their ionic salts which may be in the form of chlorides. The electrolysis is carried in the molten state. For example, electrolysis of NaCl is done to obtain sodium metal. These get deposited on the cathode of the electrolysis set up.
Hence, most electropositive metals are isolated from their ores by electrolysis of their fused ionic salts.

Note:
Electrolysis involves the electrode potential of ions from the salts that make them deposit at the electrodes, or to get released in the form of gases. The electrolysis of fused salts also involves putting them into electrolytic devices to get separated from their ores.