C:\Users\Vinod\Desktop\Untitled-1.pmdABOUT EDUCATORS
• 18 year experience of IIT JEE in Organic Chemistry
• Ex. Senior Faculty of Vibrant Academy, Kota and Bansal Classes, Kota
PIYUSH MAHESHWARI
• BE (Hons.)
• Author of 'Super Problems in Inorganic Chemistry',
• Ex. HOD Bansal Classes, Kota
• Ex. Senior Faculty of Vibrant Academy, Kota and Allen Career Institute, Kota
BRIJESH JINDAL
• 11 year experience of IIT JEE in Physical Chemistry
• Ex. Senior Faculty of Vibrant Academy, Kota, Allen Career Institute, Kota and Bansal Classes, Kota
Dry Test :

(iv) Cobalt Nitrate Test (Applied for few specific cations)
(1) Flame Test :
It is performed with the help of platinum coated wire which is first dipped in conc. HCl and brought in contact with given solid mixture. In this way, given salts are converted into more volatile chloride salt which impart characteristic colour to flame except Be2+ and Mg2+ cation(do not impart colour due to high ionization energy )
Cations Colour of Flame
(2) Borax Bead Test :
Formation of Bead : When Borax is heated on platinum coated wire loop, then it first swells up due to loss of water of crystallisation and covers entire portion of loop, which on further heating gives transparent crystalline Bead of sodium meta borate and Boric Anhydride (NaBO2 + B2O3).
)Borax(
I stepst
oxidising flame
Reducing flame
II stepnd
Fe2(SO4)3 (Solid mixture) Fe O .3SO2 3 3
Volatile part is displaced by boric anhydride present in borax bead
)beadboraxinpresent(OB3 32
)flamegsinoxidiinformedis boratemetaferricofBeadYellow(
323232 )BO(Fe2orOB3.OFe
metaborateFerric ofbeadyellow
Coloured d-block Bead colour Bead colour Product transformation cations in oxidising flame in reducing flame
Cu Blue Red Cu(BO ) Cu
Fe Yellow Green Fe(BO ) Fe(BO )
Cr Green Green Cr(BO ) Cr(BO )
Co Blue Blue Co(BO ) Co(BO )
Ni Brown Grey Ni(BO ) Ni
Mn Amethyst(violet) Colourless Mn(BO ) Mn(BO )
2+
3+
3+
2+
2+
2+
+3 +2
No change
No change
Note : All above colour of bead are observed in their cold condition (without touching flame.)
(3) Phosphate Bead Test :
flamereducingandflamegsinoxidiis formedishateorthophospofBeadBlue
4 )hateorthophosp(NaCoPO
Note : Colour table of phosphate Bead test is same as Borax Bead test in cold condition (without touching the flame).
(4) Charcoal Cavity Test :
This test is based on the fact that metallic carbonates when heated in a charcoal cavity decompose to give corresponding oxides. The oxides appear as coloured residue in the cavity. In certain cases, the oxides formed partially undergo reduction to the metallic state producing metallic scales. Example
(a) ZnSO4 + Na2CO3 ZnCO3 + Na2SO4
ZnCO3 ZnO (yellow when hot, white when cold) + CO2
(b) CuSO4 + Na2CO3 CuCO3 + Na2SO4
CuCO3 CuO + CO2
CuO + C Cu (Reddish scales) + CO
Cobalt Nitrate Charcoal Cavity Test : In case the residue is white during cavity test then one or two drops of cobalt nitrate solution is added and again heated in the oxidizing flame using blow pipe, different metal salts give different coloured mass as given in the table.
ZnSO4 + Na2CO3 ZnCO3 + Na2SO4
(Cobalt zincate) (Rinmann’s green)
Carbonate (CO3 2–) / Bicarbonate (HCO3
–)
dil.HCl/H SO2 4
(Salt sol .) n
+
2–
Observation [.......................................................................]
2.
CO ion gives ppt. at room temp. whereas HCO ¯ ion forms ppt. of carbonate on boiling.
Water insoluble carbonate salts are soluble in soda water (CO + H O) and CH COOH.
3
3
2–
3
2–
3
n
CO2
Boil
CO2
2HCO CO + CO + H O3 3 2 2 – 2–Boil
100°C
Pb(OAc) sol.2
(i)
(ii)
(iii)
(iv)
(v)
(i)
Identification of gas by oxidising agents (Redox reaction)
dil.HCl
CCl4
Fe (aq) 3+
2–
Observation [..................................................................................................... .......................................................................................]
dil. HCl Oxid. Agt.
dil. HCl
Note : 1.
2. 3.
As SO gas is more soluble in water, therefore effervescence is not observed during evolution of SO gas.
Bleaching action due to oxidising property is permanent, whereas bleaching action due to reducing prop. is temporary. H SO / SO exhibit better reducing properties and weaker oxidising property.
2
2
2
excess conc. HNO3excess NaOH
Sulphide (S2–)
1. All S2– salts of ...................... metals are water soluble and colourless whereas S2– salts of ...................... are water insoluble and usually coloured due to polarisation effect. 2. S2– salts of ................. and .............do not exist in aqueous solution because they readily hydrolysed into corresponding metal hydroxide due to their low Ksp, hence they are
prepared in dry condition. Fe3+ shows redox reaction with S2– ions. [Fe+3 + S2– Fe+2 + S] 3. ................. is the only black metal sulphide salt decomposed by non-oxidising acid (like dil.HCl/dil.H2SO4) whereas other remaining black sulphide are dissolved in oxidising acid
(hot and dil. HNO3) except ............ (Insoluble in hot and dil. HNO3 but soluble in aquaregia and S2– salt solution)
FeS(black) + dil. 2HCl / dil. H2SO4(non-oxidising acid) apparatusKipps
inoccurs.Rxn ...............................
Warm
2– +
turn .............]
(a)
(b)
(c)
(d)
(e)
(f)
(g)
Identification of gas by oxidising agents (Redox reaction)
dil.HCl
CaOCl2
CaCl2/BaCl
Hot & dil. HNO3
NH2
(1)
Observation [Colourless poisonous gas having rotten egg smell, turns Pb(CH COO) paper black (PbS)]3 2
co n
c. H
N O
3
Note : 1. Mn+ (p and d-block metal cation) forms metal suphides with H2S gas depending upon acidic, neutral, basic medium of solution
2. PbS (black) is insoluble in excess NaOH solution or excess NH4OH solution due to its low Ksp
3. Specific test with Na2[Fe(CN)5NO] (sodium nitroprusside) requires high conc. of S2– ion, hence neutral H2S and acidified H2S gives negative test, whereas alkaline H2S gives purple colouration.
Thiosulphate (S2O3 2–)
1. All S2O3 2– salts of s-block are water soluble except : ...................................
2. S2O3 2– salts of .............................................................................. are water insoluble.
Warm (I.M.R.)
(3)
(a)
(a)
(b)
Warm or standing Warm or standing Warm or standingExcess Hypo
Excess Hypo
Excess Hypo
(Complex reagent)
Pb(OAc) solution2 AgNO solution3 Hg(NO solution3)2 [Ni(en) ](NO )3 3 2
Chelating Agt
2– +
2–
Excess Cl2
(Soluble complex) Hypo is used as fixing agent in photography
(SO +S )4
2–
Note : 1. Na2S2O3(Hypo. soln) mainly exhibits reducing character. 2. Hypo solution acts as Antichlore (removes excess Cl2 from bleached cotton fabric) like SO2.
Acetate (CH3COO–)
1. All CH3COO– salts are water soluble except CH3COO– salt of Ag+ , Hg2 2+, Cu+
CH ¯ (aq)3COO
CH3 COOH (Vinegar smelling colourless vapours)
CaCl soln.2
(blood red ppt.)
Warm (1)
+
3Fe(OH) (CH COO)2 3
Note : Deep red colouration is obtained by reaction of Fe3+ cation with SCN– (aq) and CH3COO– (aq).
Nitrite (NO2¯) and Nitrate (NO3 –)
1. All NO2¯ salts are water soluble except NO2¯ salt of ............................................... 2. All NO3¯ salts are water soluble.
NO ¯ (aq)3 NO ¯ (s)3
dil.HCl/dil.H SO2 4
conc.H SO2 4
NO2(brown gas)
Test with compounds containing – NH gp.2
(Brown ring specific test)
(Brown ring specific test)
(a)
(b)
(c)
(c)
(a)
(b) No ppt. reaction because all nitrates are water soluble
With piece of filter paper or copper turnings evolution of reddish brown gas is intensified
Note: 1. Aq. soln. of M(NO2)2 / M(NO3)2 salts (M2+ = ............................) do not give brown ring test because these cations form insoluble SO4 2– salts with H2SO4 used in ring test,
formation of ppt. will create turbulence in soln. therefore, brown ring complex is not formed. In such cases, above test can be modified by first adding Na2SO4 soln. Now obtained filtrate can be used for ring test.
2. Ring test for ............ ion in presence of ................should not be done however ring test for .................... ion in presence of .................... can be performed. 3. HNO2 exhibits better oxidising character and weak reducing character.
Chloride (Cl–) , Bromide (Br–) and Iodide (I–)
1. All Cl– salts are water soluble except ................................................................................................ 2. All Br– salts are water soluble except ................................................................................................ 3. All I– salts are water soluble except .................................................................................................
CuI2 (yellow) (IMR)
conc. H SO2 4
Specific tests
C hrom
y l
chloride test
for C
l¯ io
n T
est fo
r B
r¯, I¯
C C
l layer
2 7
2 2
Pb(OAc) soln.2 AgNO soln.3
Starch
conc.H SO (few drop) x 2 2 7
2 4
then St. Oxd. Agt. like MnO is used and
if we want HX then non-oxd. acid H PO
is used.
Note : 1. ...................................................................................................................................do not give chromyl chloride test due to low concentration of Cl– ion.
2. CH3COOH used in chromyl chloride test neutralises excess NaOH otherwise yellow ppt. of PbCrO4 is not formed.
Fluoride (F–)
1. MgF2, CaF2, SrF2 and PbF2 are water insoluble fluoride
HFHF
SiF4
(b)
Solid mix (F¯ salt) + conc. H SO (few drops)2 4 HF
SiF4H SiO2 3H SiF2 6[ ]
(1) Specific Test for F¯ ion.
(c)
Glass rod dipped into water
conc. H SO2 4
Na FeF ]3 6 [
with oxidising agents
2–
Moisten glass rod (Partial hydrolysis)
SiO2
+
Etching of glass
Note : HF is only acid which reacts with glass (Etching of glass) therefore in Lab it is kept in wax coated glass vessel.
SiO2 + HF SiF4 (aq) + H2O (glass)
Oxylate (C2O4 2–)
1. Oxalate salt of alkali metals are water soluble. 2. Oxalate salts of alkaline earth metals are either water insoluble or sparingly water soluble except BeC2O4 (completely water soluble)
order of solubility in water : lelubsowater
42
lelubinsoWater
42424242 OBeCOBaCOSrCOCaCOMgC (order is similar to F¯ salt)
3. BaC2O4 is only water insoluble oxalate salt dissolved in weak acetic acid due to its relative high Ksp at R.T..
4. Oxalate salts of Ag+ , Hg2 2+, Cu+, Pb2+ are water insoluble.
Conc. H SO2 4
C O (aq.)2 4
Warm
(3)
Test based on Precipitation reaction Test based on Reducing prop. (a) (b)
60ºC KMnO + dil. H SO4 2 4
In above Redox titration
acts as self indicator
(1)
Note : H2C2O4 / C2O4 2– can act as reductant but does not act as oxidant.
Borate (BO3 3– / B4O7
2–)
1. Borate salts of s-block are water soluble and other borate salts are either water soluble or sparingly water soluble. 2. Very few borate salts derived from boric acid (H3BO3) are known, mostly borate salts are derived either from metaboric acid (HBO2) or tetraboric
acid (H2B4O7)
3– 2–
(1) Warm
(i) (ii)
(R = – CH , – C H )
Warm Warm
Solid B O salt + Conc. H SO (few drops) + CaF (s)
4 7
2 4
SO4 2– (aq) Anion
All SO4 2– salts are water soluble except sulphate salts of Ba2+, Sr2+, Pb2+ and Hg2+
SO (aq.)4
dil. HCl
excess NaOH
conc. HNO3
Hg(NO )3 2sol . n
(a) Specific test (Lab test) (b) Test based on Precipitation reaction (c)
Note : BaSO4 , SrSO4 and PbSO4 salts are insoluble in any dil. acid at room temp. due to their low Ksp.
Phosphate (PO4 3–)
1. 1°, 2° and 3° phosphate salts of alkali metals are water soluble. 2. 1° phosphate salts or alkaline earth metals are water soluble whereas their 2° and 3° phosphate salts are water insoluble. 3. 3° phosphate salts are water insoluble except alkali metal phosphate salts and (NH4)3PO4.
Note : AsO4 3– ion also give same colour ppt. with ammonium molybedate soln. but on boiling (distinction between PO4
3– and AsO4 3–ion)
PO (aq.)4
(Magnesia mixture)
molybedate soln. (lab test) (b)

V group filtrate with Mg cation is called magnesia mixture
(Specific Test for Mg )
2– 2–
1. All CrO salts of s-block are water soluble except4
2– .............. (yellow ppt.)
and ...............(only yellow chromate salt soluble in weak acetic acid.)
2. CrO salts of .............................................. are water insoluble.4
2–
3. CrO & Cr O ion exist in equilibrium depending upon pH of solution.4 2 7
2– 2–
Oxd. prop. (3)
2– 2–+ 2
2– 2–
(aq) (aq)
(Yellow) (Orange)
On standing
4
2–
2+ 2+ 2+ Pb(OAc) sol .2 n
AgNO sol3
Excess NaOH sol .
n dil. HNO3
(Orange)
1. All MnO4 – (permanganate) salt are water soluble.
2. KMnO4 decomposes photochemically into MnO2 hence it is stored in dark bottle in Lab. Conversion :
H S2
ZnSO4
(catalyst)
(1)(Soda Ext.)
4
3
H O /H2 2
2+
Acidified
PbO /S O /BiO ¯ (St. Oxd. Agt.)2 2 8 3
2–
2 2
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