`FeCr_(2)O_(4)+NaOH+"air" to (A)+Fe_(2)O_(3)(A)+(B) to Na_(2)Cr_(2)O_(7)`
`Na_(2)Cr_(2)O_(7)+X overset(Delta) to Cr_(3),O_(3) Cr_(3)+Y(Delta) to Cr`
Compounds (A) and (B) are :

Options

A. `Na_(2)CrO_(4). H_(2)SO_(4)`
B. `Na_(2)Cr_(2)O_(7),HCl`
C. `Na_(2)CrO_(5),H_(2)SO_(4)`
D. `Na_(4)[Fe(OH)_(6)].H_(2)SO_(4)`

Answer

A

Explanation

`4FeCr_(2)O_(4)+8NaOH+O_(2) overset(Delta) to underset((A)) (4Na_(2)CrO_(4)) +2Fe_(2)O_(3)+4H_(2)O`
`underset((A))(2Na_(2)CrO_(4))+underset((B))(H_(2)SO_(4)) to Na_(2)SO_(4) to Na_(2)Cr_(2)O_(7)+Na_(2)SO_(4)+H_(2)O`
`{:(Na_(2)Cr_(2)O_(7)+3C to 2Na_(2)CrO_(2)+3CO),(2NaCrO_(2)+H_(2)O to Cr_(2)O_(3)+2NaOH), (Cr_(2)O_(3)+2Al to Al_(2) O_(3)+2Cr):}`