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![[Post New]](/templates/default/images/icon_minipost_new.gif) 27 Mar 2007 11:18:04 IST
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Chemical tests to dist. b/w gases 1)CO2 .... turns lime water milky Ca (OH) 2 + C0 2 CaCO 3 + H 2O BUT MILINESS DISAPPEARS AFTER SOMETIME if CO2 IS TAKEN IN EXCESS CaCO3 + H2O + CO2-----> Ca (HCO3)2 2) H2S rotten eggs like smell turns moist lead acetate ppr black (CH3COO)2Pb + H2S -----> PbS + 2 CH3COOH
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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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27 Mar 2007 14:34:41 IST
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Hi Himanshu......m presenting a few points which i know...evry one, hope this is useful... CO2 when passed in lime water forms a white turbidity?.when excess gas is passed, then solution becomes clear.. CO2+ Ca(OH)2 -> CaCO3 + H2O CO2 when passed in baryta solution, a white ppt is formed..on excess passing, it turns clear.. CO2+Ba(OH)2 -> BaCO3 + H2O Carbonates of all alkali metals are stable towards heat except Li2CO3 Silver carbonates and other oxy salts of silver on strong heating form silver metal.Same is the case with mercury.This is possible for none others.. Tests for SO2: 1) acidic K2Cr2O7 is turned green 2) Colour of acidic KMnO4 solution is discharged 3) Colour of iodine soln is discharged 4) Acidic KIO3/ starch paper is turned blue 5) When passed in lime water, a white turbidity is formed and when excess gas is passed, a clear solution is formed. All +3 state chromium salts are green in colour....
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27 Mar 2007 14:48:47 IST
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NO2 rededish brown gas suffocating smell turns FeSO4 sol brownish black FeSO4 + NO2 + H2SO4 ------->Fe(SO4)3 + H2O + NO NH3 COLOURLESS GAS WID AMMONICAL SMELL TURNS NESSLER'S REAGENT (k2HgI4) REDDISH BROWN K2HgI4 + KOH + NH3 -----> NH2HgO.HgI (MILLON'S BASE) +KI +H2O
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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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27 Mar 2007 15:15:42 IST
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Tests for H2S: 1) colour of acidic K2Cr2O7 changes to green and yellowish white ppt is formed 2) colour of acidic KMnO4 is discharged and yellowish white ppt is formed 3) colour of iodine solution is discharged and yellowish white ppt is formed I2 + H2S -> 2HI + S colloidal sulphur is formed. 4) lead acetate paper is turned black H2S + (CH3COO)2Pb -> PbS + 2CH3COOH 5) cadmium acetate paper is turned yellow H2S + (CH3COO)2Cd -> CdS + 2CH3COOH
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27 Mar 2007 16:17:03 IST
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Q1- In a saturated solution of AgCN, if HCN gas is passed, what will be the impact on ionisation of AgCN and its precipitation? A1- CN- ion is common ion for both AgCN and NaCN. In a saturated solution of AgCN, equilibrium exists. As common ion is present, reaction shifts to the left i.e precipitation of AgCN occurs due to presence of common ion. AgCN <--> Ag+ + CN- HCN <--> H+ + CN- hey good job done kghedrui and chimanshu. people common, add to this.
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27 Mar 2007 23:27:20 IST
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good job
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where there is a will there is a way |
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28 Mar 2007 12:03:09 IST
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thanx...........
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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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30 Mar 2007 12:09:09 IST
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good one
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chak do phatteeeee........... |
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11 Oct 2007 20:03:57 IST
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nice topic
i wish all can continue this....
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11 Oct 2007 20:19:46 IST
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good job very useful
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11 Oct 2007 21:54:00 IST
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nice ones.....
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11 Oct 2007 21:57:28 IST
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gud work guys!!
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15 Oct 2007 23:22:09 IST
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test for nitrates:(NO3- )
1)when salt is heated with copper turnings only brown gas N02 is evolved.
when passed through neutral ferric chloride turns the soln. brownish black
2)Brown Ring Test : Nitric acid is produced at the interface between the nitrate solution and the conc sulphuric acid. The nitric acid is reduced to nitrogen monoxide by the iron(II) ions and the brownish violet nitroso complex is then formed by nitrogen monoxide with the excess iron(II) ions. 6 FeSO4 + 2 HNO3 + 3 H2SO4 ? 3 Fe2(SO4)3 + 2 NO + 4 H2O
[Fe(H2O)6]SO4 + NO ? [Fe(H2O)5NO]SO4 + H2O
3)diphenyl amine when added to aq. soln of salt blue solution obtained
diphenyl amine or Phenylbenzenamine is an aromatic amine with the structural formula (C6H5)2NH
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17 Oct 2007 12:48:09 IST
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