P Block Elements (Grp - 15) Flashcards
MP of Hydrides
PH₃ < AsH₃ < SbH₃ < BiH₃ < NH₃
NH₃ forms intramolecular H-Bonding
BP of Hydrides
PH₃ < AsH₃ < NH₃ < SbH₃ < BiH₃
NH₃ forms intramolecular H-Bonding
Common oxidation State
+3, +5, -3
N : +1,+2,+3,+4,+5,-5
Bi : hardly -3
Covalency
5 or 6
N : 4 (tendency to for pπ-pπ bond)
Down the grp
NH₃
PH₃
AsH₃
SbH₃
BiH₃
Bond angle ↓ (as only NH₃ is hybridised ~ 107°, others 90°)
E-H bond energy ↓
Reducing power ↑
Acidity ↑ (easy to release H⁺)
ECl₃ + H₂O
NCl₃ + H₂O → NH₃ + HCl
PCl₃ + H₂O → H₃PO₃ + HCl
AsCl₃ + H₂O → As₂O₃ + HCl
SbCl₃ + H₂O → SbOCl + HCl
BiCl₃ + H₂O → BiOCl + HCl
EOCl - Element Oxychloride
E³⁻ + M⁺
Ca⁺² + N³⁻ → Ca₃N₂
Na⁺ + N³⁻ →Na₃N
Ca²⁺+ + P³⁻ →Ca₃P₂
Zn + Sb³⁻ → Zn₃Sb₂
Fractional Distillation of liquid air
Preparation of N₂
NH₄Cl + NaNO₂ Δ→ N₂ + H₂O + Nacl
(NH₄)₂Cr₂O₇
Preparation of N₂
(NH₄)₂Cr₂O₇ / Δ→N₂ + H₂O + Cr₂O₃ (Green)
NaN₃ Δ→
Ba(N₃)₂ Δ→
Preparation of N₂
NaN₃ Δ→ Na + N₂
Ba(N₃)₂ Δ→ Ba + N₂
Haber’s Process
Preparation of Ammonia
N₂ + 3H₂ → 2NH₃
CATALYST
200 atm
450 - 500°C
Mo - Promoter
Fe(FeO.K₂O.Al₃O₂) - Iron Catalyst
N₂ + O₂ / Δ→
N₂ + O₂ / Δ→ 2NO
Ammonium salt + Base → NH₃
Preparation of Ammonia
NH₄Cl + KOH → NH₃ + KCl + H₂O
(NH₄)₂SO₄ + NaOH → NH₃ + Na₂SO₄ + H₂O
Fe³⁺ + NH₄OH
Fe³⁺ + NH₄OH → Fe(OH)₃
[Do not react with further NH₄OH]
Al³⁺ + NH₄OH
Al³⁺ + NH₄OH → Al(OH)₃
[Do not react with further NH₄OH]
Cu²⁺ + NH₄OH
Cu²⁺ + NH₄OH → Cu(OH)₂ + NH₄OH → [Cu(NH₃)₄]²⁺ - Deep blue
Zn²⁺ + NH₄OH
Zn²⁺ + NH₄OH → Zn(OH)₂ + NH₄OH → [Zn(NH₃)₄]²⁺ - Clear soln
AgCl + NH₄OH
AgCl + NH₄OH → [Ag(NH₃)₂]Cl
NH₄⁺ + K[HgI₄] (Nessler’s reagent)
NH₂.HgO.HgI - Iodide of millon’s base
Test for NH₄⁺
PbO + NH₃
CuO + NH₃
NH₃ - Weak Reducing agent
PbO + NH₃ → Pb + N₂ + H₂O
CuO + NH₃ →Cu + N₂ + H₂O
N₂ + Cl₂
N₂(excess)+ Cl₂ → NH₄Cl + N₂
N₂ + Cl₂(excess) → NCl₃ + HCl
NH₃ + O₂ in Pt/Rh
NH₃ + O₂ in Pt/Rh → NO + H₂O
Oxides of Nitrogen
Refer Notes
Ostwald’s Process
Pt/Rh
NH₃ + O₂ + Pt/Rh→ NO + H₂O
NO + O₂ → NO₂
NO₂ + H₂O → HNO₃ + NO
HNO₃ + NaOH
HNO₃ + NaOH→ NaNO₂ + H₂O
acidic nature of HNO₃
Oxidation of metals and non- metals by HNO₃
Refer notes
Brown ring test
Identify NO₃⁻ (Nitrate ion)
NO₃⁻ + Fe²⁺ → NO + Fe³⁺ + H₂O
NO + Fe²⁺ + H₂O → [Fe(H₂O)₅NO]²⁺ (Brown Ring)
white P₄ + O₂
P₄ + O₂ → P₄O₁₀ - vapour of P₄ (Poisonous)
white P₄ + NaOH
white P₄ + NaOH → PH₃ + NaH₂PO₂ + H₂O
disproportionation rxn
white P₄ + 573 K
white P₄ + 573 K ⇄ Red P₄
Transition Temp. = 573K
Preparation of Phosphine
Zn₃P₂ + dil.HCl → ZnCl₂ + PH₃
Ca₃P₂ + H₂O→ Ca(OH)₂ + PH₃
Purification of PH₃
PH₃ + HI → PH₄I + Impurities
PH₄I + KOH → PH₃(pure) + H₂O + KI
Holme’s signal
CaC₂ + Ca₃P₂
CaC₂ + H₂O →C₂H₂ + Ca₃P₂ → PH₃
This mixture produces impure PH₃ (Phosphine) - gives signal in smokescreen, etc
Properties of PH₃
PH₃ + CaSO₄ → Ca₃P₂ + H₂O
PH₃ + HgCl₂→ Hg₃P₂ + H₂O
PH₃ + HCl→PH₄Cl
Oxides of P
Refer notes
Halides of P
Refer notes
Oxoacids of P
Refer notes
α - Black P
Red P + 803 K in sealed tube
β- Black P
White P + 473 K in sealed tube
N
P
As
Sb
Bi
Down the grp
Size ↑
Ionisation potential (∆iH) ↓
BP ↑ [Ex. Sb>Bi]
MP ↑ [Till As and decrease]
Electron affinity
Grp 15 < Grp 16
Bcas grp 15 has half filled config. which is quite stable
Fajan’s Rule
sai - small anion - ionic
EX₃ > EX₅
EX₅ is more covalent due to big anion (more anion)
or +5 in EX₅ - more polarising
