Sodium aluminate solution is converted into Al(OH)3 in Hall's process by (i) and in Baeyer's process by (ii) .

passing CO2; diluting and seeding with freshly precipitated Al(OH)3

heating with coke; passing steam

diluting and seeding with Al(OH)3; passing CO2

adding excess dilute HCl; passing CO2

passing CO2; diluting and seeding with freshly precipitated Al(OH)3

JEE Main levelSingle correct optionDifficulty 2 of 3mt026

Sodium aluminate solution is converted into $Al (OH) X_{3}$ in Hall's process by (i) and in Baeyer's process by (ii) .

Aheating with coke; passing steam
Bdiluting and seeding with $Al (OH) X_{3}$ ; passing $CO X_{2}$
Cadding excess dilute $HCl$ ; passing $CO X_{2}$
Dpassing $CO X_{2}$ ; diluting and seeding with freshly precipitated $Al (OH) X_{3}$

In Hall's process the bauxite is fused with

Na X_{2} CO X_{3}

and the aluminate solution is acidified by

CO X_{2}

to give

Al (OH) X_{3}

. In Baeyer's process the aluminate in strong alkali is diluted and seeded with fresh

Al (OH) X_{3}

so that it hydrolyses back. Excess strong acid would redissolve the hydroxide.