The steps, in one of the possible reaction mechanisms, corresponding to the preparation of acetone from isopropyl alcohol by using $\mathrm{CrO}_3$ and conc. $\mathrm{H}_2 \mathrm{SO}_4$ are mentioned below.
Step 1: $\mathrm{CH}_3 \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_3 \xrightarrow{\mathrm{H}_2 \mathrm{CrO}_4} \quad X+Y$

Step 2: $\mathrm{X}+\mathrm{H}_2 \mathrm{O} \longrightarrow$ Acetone $+\mathrm{Z}+\mathrm{Q}$ (Cr containing species)

Step 3: $\mathrm{Q}+\mathrm{H}^{+} \longrightarrow \mathrm{E}+\mathrm{F}+\mathrm{H}_2 \mathrm{O}$
Here, Z is $\mathrm{H}_3 \mathrm{O}^{+}, \mathrm{E}$ and F are Cr -containing species, and Step 3 is a disproportionation reaction. The correct statement(s) is/are

• Correct answer
  A

  $\mathrm{Y}=\mathrm{H}_2 \mathrm{O}$ and X contains chromium in oxidation state +6 .
• Correct answer
  B

  Oxidation states of chromium in E and F are +6 and +3 .
• C

  In Step 2, water acts as an acid.
• Correct answer
  D

  Oxidation state of chromium in the compound Q is +4 .

Hence, the correct answer is options: 'A', 'B', 'D'.