Reagents

Question 1

Reagent No.1:NaOH

Answer 1

NaOH
i)M forms basic hydroxide
M+ + NaOH—->M(OH)x
ii)M forms amphoteric hydroxide
M+ + NaOH—->M(OH)x
M(OH)x + excess NaOH—->Nay[M(OH)(x+y)]

Question 2

reagent no.1 rxn with
i)Be+2

ii)Zn+2
iii)Al+3
iv)Cr+3
v)Cu+2

Answer 2

i)Be+2 + NaOH—->Be(OH)2+ excess NaOH—->Na2BeO2
white
ii)Zn+2 + NaOH—->Zn(OH)2 + excess NaOH—>Na2ZnO2
iii)Al+3 + NaOH—->Al(OH)3 + excess NaOH—->Na2AlO2
iv)Cr+3 + NaOH—->Cr(OH)3 + excess NaOH—->NaCrO2

Question 3

Reagent Number 2:NH3/NH4OH

Answer 3

M!=NH4+,IA,Ba,Sr,Ca
i)p block and Fe,Mn,Hg
M+x + NH3—->M(OH)x
ii)d block except Fe,Mn,Hg
M+x + NH3—->M(OH)x
M(OH)x + excess NH3—-> complex

Question 4

NH4OH reagent reaction with:
i)Zn+2
ii)Ni+2
iii)Cr+3
iv)Cu+2
v)Cd+2
vi)Co+2

Answer 4

i)Zn+2 —->Zn(OH)2—->[Zn(NH3)4]+2 cleae
ii)Ni+2 —->Ni(OH)2—->[Ni(NH3)6]+2 blue
iii)Cr+3—->Cr(OH)3—->[Cr(NH3)6]+3 pink
iv)Cu+2—->Cu(OH)2—->[Cu(NH3)4]+2 Blue
v)Cd+2—->Cd(OH)2—->[Cd(NH3)4]+2 clear
vi)Co+2 —->Co(OH)2—->[Co(NH3)6]+2 colored

Question 5

Reagent number 3:KI

Answer 5

M+x—->MIx
M = Ag+,Cu+,Pb+2,Hg+2,Hg2+2,Bi+3

i)P block or Hg
soluble I- complex
ii) d block
no reaction
redox reaction with Cu+2

Question 6

rxn with reagent 4 :KCN
i)Zn+2
ii)Cu+2
iii)Fe+2
iv)Fe+3

Answer 6

i)Zn+2—->Zn(CN)2—->Zn(CN)4 -2 clear
ii)Cu+2—->Cu(CN)+(CN)2—->K3[Cu(CN)4] clear
iii)Fe+2—->Fe(CN)2—->K4[Fe(CN)6] yellow
iv)Fe+3—->Fe(CN)3—->K3[Fe(CN)6] yellow

Question 7

rxn with reagent KI:
i)Cu+2
ii)Ag+
iii)Pb+2
iv)Hg2 +2
v)Hg+2
vi)Bi+3

Answer 7

i)Cu+2—->Cu2I2+(I2+KI3)
ii)Ag+—->AgI
iii)Pb+2—->PbI2—->PbI4-2
iv)Hg2 +2—->Hg2I2—->Hg(black)+HgI4-2(clear solution)
v)Hg+2—->HgI2—->HgI4-2(clear solution)
vi)Bi+3—->BiI3—->BiI4-(yellow brown)

Question 8

Fourth Reagent:KCN

Answer 8

M+x—->M(CN)x
M!=IA,IIA,Hg+2,NH4+
i)p block
M(CN)x—->complex
ii)
M(CN)x—>no rxn
Cu+2 shows redox reaction with CN-

Question 9

solubility in SA(H2SO4,HCl,HNO3) and WA(CH3COOH)
i)salts of CO3-2
ii)salts of CrO4-2
iii)salts of C2O4-2
iv)salts of SO4-2

Answer 9

i)All are soluble in SA and WA
ii)All are soluble in SA
only SrCrO4 are soluble in WA
iii)All are soluble in SA
only BaC2O4 are soluble in WA
iv)None are soluble in dil SA but soluble in conc.H2SO4
SO4-2+conc.H2SO4—->H2O+HSO4-

Question 10

which sulphides will precipitate in
i)H2S/H+
ii)H2S
iii)H2S/OH-

Answer 10

i)Ag+,Hg2 +2,Pb+2
Pb+2,Cu+2,Bi+3,Hg+2,Cd+2
Sb+3/+5,Sn+2/+4,As+3/+5
ii)previous + Zn+2
iii)all except IA,IIA,NH4+

Question 11

fifth reagent S2O3-2

Answer 11

M+x—->M2(S2O3)x—->complex
M=Ag+,Bi+3,Cu+,Hg+2,Hg2 +2,Ba+2,Pb+2
Cu+2 shows redox rxn with S2O3-2

Question 12

rxn with S2O3-2
i)Ag+
ii)Bi+3
iii)Pb+2
iv)Cu+2

Answer 12

i)Ag+—->Ag2S2O3—->[Ag(S2O3)2]-3
ii)Bi+3—->Bi2(S2O3)3—->[Bi(S2O3)]-
iii)Pb+2—->PbS2O3—>[Pb(S2O3)2]-2
iv)Cu+2—->Cu2S2O3+S4O6-4—->[Cu6(S2O3)5]-4

Question 13

Dissolution of insoluble sulfide

Answer 13

i)all insoluble black color sulfides are soluble in HCl except FeS
ii)HNO3 is better for dissolution
iii)Except HgS all insoluble sulfides are soluble in hot and dilute HNO3
iv)Only MnS is soluble in CH3COOH among insoluble sulfide