The function of potassium ethyl xanthate in froth floatation process is to make the ore

• water repellant

• lighter

• heavier

• attracted towards water

From the Ellingham graphs on carbon, which of the following statements is false?

• CO reduces Fe₂O₃ to Fe at less than 983 K

• CO is less stable than CO₂ at more than 983 K

• CO reduces Fe₂O₃ to Fe in the reduction zone of blast furnace

• CO₂  is more stable than CO at less than 983 K

The ore that is concentrated by the froth floatation process is

• cryolite

• cuprite

• calamine

• chalcopyrites

Copper is extracted from copper pyrites by heating in a Bessemer converter. The method is based on the principle that

• copper has more affinity for oxygen than sulphur at high temperature

• iron has less affinity for oxygen than sulphur at high temperature

• copper has less affinity for oxygen than sulphur at high temperature

• sulphur has less affinity for oxygen at high temperature

van-Arkel method of refining zirconium involves

• removing all oxygen and nitrogen impurities

• removing CO impurity

• removing hydrogen impurity

• removing silica impurity

Cryolite is

• Na₃AlF₆ and is used in the electrolysis of alumina for decreasing electrical conductivity

• Na₃AlF₆ and is used in the electrolysis of alumina for lowering the melting point of alumina only ·

• Na₃AlF₆ and is used in the electrolysis of alumina for lowering the melting point and increasing the conductivity of alumina

• Na₃AlF₆ and is used in the electrolytic refining of alumina

The metal extracted by leaching with a cyanide is

• Al

• Na

• Cu 

• Ag

Which one of the following ores is best concentrated by froth-floatation method ?

• Magnetite

• Cassiterite

• Galena

• Malachite

In electrorefining of copper, some gold is deposited as :

• cathode

• electrode

• cathode

• anode mud

Following method is not used for extraction of Al:

• Van Arkel

• Serpeck

• Baeyer

• Hall- Heroult