`FeCr_(2)`(chromite ) is a good soure of chromium and its compounds like `Na_(2)CrO_(4),Na_(2)Cr_(2)O_(7)`
` P:FeCr_(2)O_(4)+NaOH+airto A+Fe_(2)O_(3)Q:`
`A+Bto Na_(2)Cr_(2)O_(7)`
`R:Na_(2)Cr_(2)O_(7)+Xoverset(Delta)toCr_(2)O_(3)`
`S:Cr_(@)O_(3)+YtoCr`
COmpounds (A) and(B)are:-
A. `Na_(2)Cr.O_(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)`
