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![[Post New]](/templates/default/images/icon_minipost_new.gif) 24 Mar 2007 19:50:59 IST
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1.The soldiers of napolean army while at alps during freezing winter suffered a serious problem as regards to the TIN buttons of thier uniforms.White metallic tin buttons got converted to grey powder.This transformation is why? 2.conjugate base of H2PO4-
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24 Mar 2007 20:29:09 IST
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because below 291 k , white tin gets converted into grey
grey is brittle hence it crumbles down and gets corroded
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I always like to walk in rain as no one can see me crying there :(
frnds are like diamonds , if u hit them , they don't break but they slip frm ur hands
-----It is better to be hated for what you are than to be loved for what you are not.----
*****wen love and skill work together--expect a masterpiece*****
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24 Mar 2007 20:34:46 IST
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himanshu is ryt about the 1st one . 2 . HPO4 -2
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light travels the fastest ??? NO
wherever light goes it always finds that darkness has already got there |
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24 Mar 2007 20:38:48 IST
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ya the grey will be below the low temparature himanshu is right
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jo dar gaya so mar gaya |
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24 Mar 2007 20:39:36 IST
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plz rate me
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I always like to walk in rain as no one can see me crying there :(
frnds are like diamonds , if u hit them , they don't break but they slip frm ur hands
-----It is better to be hated for what you are than to be loved for what you are not.----
*****wen love and skill work together--expect a masterpiece*****
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Below 13.2 0C, tin exists as gray or alpha tin, which has a cubic crystal structure. Gray tin has no metallic properties at all, it is a dull-gray powdery material.
Metallic white tin will slowly convert to gray tin if it is held for a long time below 13.2 °C.
The metallic surface of white tin becomes covered with a gray powder which is easily rubbed off. The gray patches slowly expand until all of the tin in the object is converted from the metal to the powder, at which point it loses its structural integrity and may fall to pieces. This process is known as tin disease or tin pest.
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Bipin Kumar Dubey
Chemical Dept.
IIT Kharagpur
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26 Mar 2007 12:01:21 IST
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yeah alpha to beta tin occurs at 286 K as pr NCERT!!!
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Life Ka fundaa hai
Jiyo aur jino do |
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