On heating a mixture of common salt and K _ 2 Cr _ 2 O _ 7 in equal amount along with concentrated H _ 2 SO _ 4 in a test tube, a gas is evolved. Formula of the gas evolved and oxidation state of the central metal atom in the gas respectively are:
C. CrO _ 2 Cl _ 2 and +6
When a mixture of NaCl and K2Cr2O7 is heated with concentrated H2SO4, the dichromate ion oxidizes chloride ions. The reaction produces chromyl chloride (CrO2Cl), which is a volatile deep-red colored gas. The dichromate ion contains chromium in the +6 oxidation state. In the reaction, the dichromate is reduced and chloride is oxidized, but the chromium in the product remains in the +6 oxidation state as CrO2Cl (or as CrO2⁺ in ionic form). The gas evolved is CrO2Cl with chromium in the +6 oxidation state
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