(1) Metals occur in the native form because of their
(a) High electronegativity
(b) Low reactivity
( c) Low density
(d) High reactivity
(2) Specific gravity of slag is
(a) Higher than molten metal
(b) Same as that of molten metal
( c) Less as that of molten metal
(d) None of the above
(3) Which process is used for the extraction of metals from their sulphide ores ?
(a) Smelting
Froth flotation
( c) Electrolysis
(d) Metal displacement
(4) Calamine is an ore of
(a) `Hg`
(b) `Zn`
( c) `Ca`
(d) `Cd`
(5) Non-fusible impurities of ores removed by adding
Slag
(b) Flux
( c) Gangue
(d) None
(6) Common method of extraction of metals from oxide ore involves.
(a) Reduction with aluminium
(b) Reduction with carbon
Reduction with hydrogen
(d) Electrolytic method
(7) Smelting is the reduction of oxide to metal by
(a) Carbon
(b) Hydrogen
( c) Aluminimum
(d) Electric current
During froth flotation process, commonly used frother is.
(a) `CuSO_(4)`
(b) `NaCN + alkali`
( c) Pine oil
(d) Potassium xanthate
(9) Iron ores are dressed by
(a) Froth flotation process
(b) Hand picking
( c) Magnetic separation
(d) All of the above
(10) Silicon is the main constituent of
(a) Alloys
(b) Rocks
( c) Animals
Plants.

Explanation

(1) `b`
(2) `b`
(3) `b`
(4) `b`
(5) `b`
(6) `b`
(7) `a`
(8) `c`
(9) `c`
(10) `b`.