Cho sơ đồ phản ứng sau:${{\text{K}}_{\text{2}}}{\text{C}}{{\text{r}}_...

${{\text{K}}_{\text{2}}}{\text{C}}{{\text{r}}_{\text{2}}}{{\text{O}}_{\text{7}}}\xrightarrow{{{\text{ + FeS}}{{\text{O}}_{\text{4}}}{\text{ + X}}}}{\text{C}}{{\text{r}}_{\text{2}}}{{\text{(S}}{{\text{O}}_{\text{4}}}{\text{)}}_{\text{3}}}\xrightarrow{{{\text{ + NaOH d}}}}{\text{NaCr}}{{\text{O}}_{\text{2}}}\xrightarrow{{{\text{ + NaOH + Y}}}}{\text{N}}{{\text{a}}_{\text{2}}}{\text{Cr}}{{\text{O}}_{\text{4}}}$

Biết X, Y là các chất vô cơ. X, Y lần lượt là