Bauxite ore is made up of `Al_(2)O_3` + `SiO_2` + `TiO_2` + `Fe_(2)O_3` . This ore is treated with conc. NaOH solution at 500 K and 35 bar pressure for a few hours and filtered hot. In the filtrate the species present are :

Options

A. `NaAl(OH)_4` only
B. `Na_2Ti(OH)_6` only
C. `NaAl(OH)_4` and `Na_2SiO_3`both
D. `Na_2SiO_3` only

Answer

A

Explanation

In bauxite ore, only `Al_(2)O_(3)` reacts with conc. NaOH and formed sodium meta aluminate. This, further dissolves in water.
`Al_(3)O_(3) + 2H_(2) O + 2NaOH overset(500 K)underset(35 "bar") rarr 2NaAlO_(2) + 3H_(2)O`
`NaAlO_(2) + 2H_(2)O rarr NaAl(OH)_4`