FeCr2O4 + Na2CO3 + O2 [X] [Y] [Z]<br>Which of the following statement is true for the compounds [X], — d and f Block Elements Chemistry Question

💡 Solution & Explanation

Step 1: Let's identify the compounds. Fusing chromite ore (FeCr2O4) with Na2CO3 in the presence of oxygen yields sodium chromate, Na2CrO4 [X]. Acidifying Na2CrO4 forms sodium dichromate, Na2Cr2O7 [Y]. Reacting Na2Cr2O7 with H2O2 in an acidic medium yields chromium pentoxide, CrO5 [Z], which has a deep blue-violet color. Step 2: Verify the statements: (a) In Na2CrO4, Na2Cr2O7, and CrO5, chromium is in its +6 oxidation state (true). (b) CrO5 [Z] is highly unstable in water and rapidly decomposes to Cr3+ and oxygen (true). (c) Saturated sodium dichromate [Y] treated with conc. H2SO4 precipitates red crystals of chromic anhydride (CrO3) (true). Step 3: Since all the statements are correct, the answer is option (d).