191.

When CO₂ is passed through solution of sodium aluminate, precipitate of which compound is formed?

• Al(OH)₃

• Al₂O₃

• Na₂CO₃

• No ppt

Which of the following is not the correct match?

• Leaching : Ag

• Zone refining : Sn

• Liquation : Pb

• van Arkel : Zr

The purpose of smelting an ore is to :

• oxidise it

• reduce it

• obtain an alloy

• separate volatile impurities

What is the role of aniline or cresol when added in a froth floatation process?

• Stabilizer

• Depressant

• Wetting agent

• All of these

Important ore of zinc is :

• calamine

• cryolite

• zinc blende

• malachite

Maximum number of molecules of CH₃I that can react with a molecule of CH₃NH₂ are :

• 3

• 4

• 2

• 1

Which method is not used for the extraction of Al ?

• Van - Arkel

• Serpeck

• Baeyer

• Hall - Heroult

Aluminium becomes passive on treatment with :

• dil. HNO₃

• conc. HNO₃

• dil. H₂SO₄

• none of these

Oils can be converted into fats by :

• hydrogenolysis

• hydrogenation

• decarboxylation

• hydration

Carbon and CO gas are used to reduce which of the following pairs of metal oxides for extraction of metals?

• FeO, SnO

• SnO, ZnO

• BaO, Na₂O₂

• FeO, ZnO