`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 `
Na_(2)CrO_(4)and Fe_(2)O_(3)`are separated by:
A. Dissolving in conc ,`H_(2)SO_(4)`
B. Dissolving in `NH_(3)`
C. Dissolving in `H_(2)O`
D. Dissolving in dil,HCl