For coagulating As₂S₃ colloidal solution which of the following will have the lowest coagulation value?

• NaCl

• KCl

• BaCl₂

• AlCl₃

Heating pyrites to remove sulphur is called

• smelting

• calcination

• liquation

• roasting

63.

In the metallurgy of which of the following cupellation process is used?

• Copper 

• Silver

• Iron

• Aluminium

Cryolite is used in the electrolytic extraction of aluminium

• to obtained more alumimium

• to decompose bauxite

• to protect anodes

• as a reducing agents

The important ore of lead is

• chalcopyrite

• haematite

• galena

• cast iron

The iron obtained from blast furnace is

• pig iron

• wrought iron

• soft iron

• cast iron

Which of the following elements exhibits the most basic properties?

• F

• Cl

• Br

• I

Elements which generally exhibit multiple oxidation states and whose ions are usually coloured are

• metalloids

• non- metals

• tranistion elements

• gases

The transition metals mostly are

• diamagnetic

• paramagentic

• neither diamagnetic nor paramagnetic

• both diamagnetic and paramagnetic.

The correct statement in respect of d-block elements is

• they are all metals

• they show variable valency

• they form coloured ions and complex salts

• All the above statements are correct