The reaction of NaCl and K₂Cr₂O₇ with conc. H₂SO₄  results in the formation of

$\mathrm{NaCl}+{\mathrm{H}}_2{\mathrm{SO}}_4→{\mathrm{NaHSO}}_4+\mathrm{HCl}$

${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7+2{\mathrm{H}}_2{\mathrm{SO}}_4→2{\mathrm{KHSO}}_4+2{\mathrm{CrO}}_3+{\mathrm{H}}_2\mathrm{O}$

${\mathrm{CrO}}_3+2\mathrm{HCl}→{\mathrm{CrO}}_2{\mathrm{Cl}}_2+{\mathrm{H}}_2\mathrm{O}$

        Chromyl chloride