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
D.
roasting
Heating pyrites to remove sulphur is called roasting because in roasting ore is heated below its melting point in presence of air, so sulphur reacts with oxide to remove as volatile oxide.
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
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