A metal X reacts with aqueous NaOH solution to form Y and a highly inflammable gas. Solution Y is heated and CO2 is poured through it. Z precipitates out and Na2CO3 is formed. Z on heating gives Al2O3, Identify X, Y and Z. X Y Z (a) Al NaAlO2 Al(OH)3 (b) Al2O3 NaAlO2 Al2CO3 (c) Al2O3 [Na2AlO2]+OH– Al(OH)3 (d) Al Al(OH)3 Al2O3

Aluminium on reaction with NaOH gives Sodium alumi- nate and hydrogen as flammable gas. Sodium aluminate on heating and pouring with carbon dioxide gives alu- minium hydroxide and sodium carbonate. Also alu- minium hydroxide on heating gives alumina. Therefore, option A is correct. 2 2 2 2 2 2 3 2 3 3 2 3 2Al 2NaOH 2H O 2NaAlO 3H NaAlO CO H O 2Al(OH) Na CO Al(OH) Al O D D + + ® + ­ + + ¾¾® ¯ + ¾¾®