An inorganic compound (A) shows the following reactions
i) It is white solid exists as dimmer and gives fumes of (B) with wet air
ii) It sublimes in 180∘C and form monomer If heated to 400∘C
iii) Its aq solution turns blue litmus to red.
iv) Addition of NH4OH and NaOH separately to a solution of (A) gives white ppt
which is however soluble in excess of NaOH. What is 'A'
Al2Cl6
'A' is the white solid existing as dimmer
⇒ A may be AlCl3 existing as Al2Cl6 (White)
i) When Al2Cl6 is exposed to moist air
Al2Cl6+6H2O→2AI(OH)3+6HCl
(fumes of HCl and colloidal Al(OH)3
ii) when (A) is heated to 180∘C it sublimes to give
Al2Cl6180∘C−−−→Al2Cl6(g) and when heated to 400∘C it gives monomer
Al2Cl6400∘C−−−→2AlCl3
iii) When heated with NH_4OH and NaOH separately give
Al2Cl6+6NH4OH→2Al(OH)3↓6NH4Cl
(whiteppt)
and Al2Cl6+6NaOH→2Al(OH)3↓6NaCl
(whiteppt)
again Al(OH)3+NaOH→NaAlO2+2H2O
(excess)(Soluble)