er.arun88 wrote:
can someone please help me with Question 2 and 4?.
There are only 3 Questions... So I assume u need help with Q2
According to the passage, the natural passivization layer on the surface of aluminum metal --->
Its asking what can be inferred abt Natural Passivization layer on the Surface of Al metal. So lets read the content of it..... i.e. The surface of pure aluminum instantly combines with atmospheric oxygen to form a thin but robust “passivization” seal of aluminum oxide that prevents further corrosion. ==>
Metal Aluminium prevents further corrosion which implies...there is no further damage .Many other metals, such as iron, are less reactive than aluminum, but their superficial oxides do not form as swiftly, completely, or impermeably.==>
Aluminium is more reactive than other metals.Till this end, we can infer that either Aluminium has special characteristic or benefit. SO let's check the choices.(A) causes atmospheric oxygen to react chemically with the metal ---
Aluminium combines with atmospheric oxygen to form oxide, but AL is not the cause.(B) is less impenetrable than typical iron oxide films formed on pure iron ---
It is mentioned that "...but their superficial oxides do not form as swiftly, completely, or impermeably" ==> their refers to other metals and their oxides are not as impermeable as Al, so this implies AL is more impenetrable---This choice is opposite of what is stated in the passage..
(C) lowers the utility of aluminum in its uncontaminated state ---
No info given about its uncontaminated state.(D) provides aluminum with a chemical advantage, relative to other metals ---
this is something similar we inferred(E) precludes the inexpensive purification of the metal by traditional chemical processes ---
Cryolite does it not the Surface layer of ALSo the option which can be inferred is . D
Hope this helps !