Which of the following is not an iron ore?

• Malachite

• Haematite

• Siderite

• Limonite

The process in which metal surface is made inactive is called

• passivation

• galvanising

• corrosion

• pickling

What is the most abundant element on earth?

• Hydrogen

• Nitrogen

• Oxygen

• Silicon

Which among the following alloys is used in making instruments for electrical measurements?

• Stainless steel

• Manganin

• Spiegeleisen

• Duralumin

Name the metal that is purified by placing the impure metal on sloping hearth of a reverberatory furnace and heating that above its melting point in the absence of air.

• Mercury

• Gallium

• Zirconium

• Copper

How is ore of aluminium concentrated?

• Roasting

• Leaching

• Froth floatation

• Using Wilfley table

Name the reagent that is used in leaching of gold.

• Carbon

• Sodium cyanide

• Carbon monoxide

• Iodine

208.

Which among the following is not is mineral of iron?

• Haematite

• Magnesite

• Magnetite

• Siderite

Name the process that is employed to refine aluminium.

• Hall's process

• Mond process

• Hoope's process

• Serperck's process

Purification of aluminium by electrolytic refining is called

• Hall's process

• Froth flotation process

• Bayer's process

• Hoop's process