When metals X is treatedwith sodiumhydroixdes , a whiteprecipitate (A) isobtained , which is solublein excess of NaOHto give soublecomplex (B). Compound(A)is soublein diluteHCl to form compound (C ). Thecompound (A)when heatedstronglygives (D), which isused to extractmetal.Identify(X), (A), (B), (C ) and (D).Write suitable equationsto supporttheir identities.

When metals X is treatedwith sodiumhydroixdes , a whiteprecipitate (A)

1.	When metals X is treatedwith sodiumhydroixdes , a whiteprecipitate (A) isobtained , which is solublein excess of NaOHto give soublecomplex (B). Compound(A)is soublein diluteHCl to form compound (C ). Thecompound (A)when heatedstronglygives (D), which isused to extractmetal.Identify(X), (A), (B), (C ) and (D).Write suitable equationsto supporttheir identities.
Answer» Solution :Since metal X reacts with `NaOH`to first GIVE a white ppt. (A) which dissolves in excess of NaOH to give a soluble complex (B), therefore , metal (X) must beAl , ppt (A)must be `Al(OH)_(3)`and complex (B) must be sodium tetrahydroxoaluminate (III). `{:(underset((X))(2Al) + 3NaOH rarr underset(" Aluminium hydroxide (ppt.) ")(Al(OH)_(3)darr) + 3Na^(+)),(underset((A))(Al(OH)_(3))+NaOHrarr underset("Sod. tetrahydroxoaluminate (III)")underset((B))(NA^(+)[Al(OH)_(4)]^(-))):}` Since (A), i.e,`Al(OH)_(3)` react with DIL. `HCl` to give compound(C), therefore, (C ) must be `AlCl_(3)`. `underset((A))(Al(OH)_(3)) + 3HCl rarr underset((C ))(AlCl_(3)) + 3H_(2)O` Since (A)on heatinggives (D)which is used to extract metal (i.e, electrolysis of `Al_(2)O_(3)` gives Al metal), therefore , (D) must bealumina `(Al_(2)O_(3))` `underset((A))(2Al (OH)_(3)) OVERSET(Delta)rarr underset((D)) (Al_(2)O_(3)) + 3H_(2)O`