(a) On bolining a mineral `(A)` with `Na_2CO_(3)` solution, a white precipirtate `(B)` is formed.
(b) The precipitate is fitered and the filtrate contains two conpounds `( C)` and `(D)`. The componds `( C)` is removed by crystallisation and when `CO_(2)` is passed through the mother liquor left, `(D)` changes to `( C)`.
( c) On strongly heating `( C)`, two compounds `(D)` and `( E)` are formed.
(d) `(E)` on heating with cobalt oxide provides blue-coloured substance `(F)`.
Identify `(A)` to `(F)` and give chemical reaction for `(a)` to `(d)`.

Explanation

(a) The mineral (A) is colemanite `Ca_(2)B_(6)O_(11)*5H_(2)O`
`Ca_(2)B_(6)O_(11)+2Na_(2)CO_(3(aq)) overset("boiled")to2underset(B)(2CaCO_(3))+underset(C)(Na_(2)B_(4)O_(7))+underset((D))(NaBO_(2))` soluble.
(b) (C) the borax is crystallized.
the mother liquor consisting sodium metaborate is treated with `CO_(2)`
`4NaBO_(2)+CO_(2) to Na_(2)B_(4)O_(7)+Na_(2)CO_(3)`
(c) `Na_(2)B_(4)O_(7)*10H_(2)O overset("heated")tounderset("Anhydrous")(Na_(2)B_(4)O_(7))+10H_(2)O`
`Na_(2)B_(4)O underset("heated")overset("strongly")to underset((D))(2NaBO_(2))+underset((E))(B_(2)O_(3))`
(d) `CoO+underset((E))(B_(2)O_(3)) overset(Heat)to underset("Cobalt meta borate blue coloured (F)")(Co(BO_(2))_(2))`