Multiple Choice QuestionsFor coagulating As2S3 colloidal solution which of the following will have the lowest coagulation value?
NaCl
KCl
BaCl2
AlCl3
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
C.
tranistion elements
Transition elements exhibit multiple oxidation states because transition elements have their valence electrons in two different sets of orbitals, i.e. (n -l)d and ns. Since there is very little difference in the energies of these orbitals, both energy levels can be used for bond formation.
Note: First and last member of transition series doesn't exhibit multiple oxidation states.
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
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