Chemistry · Some Basic Concepts of Chemistry (Mole Concept) + Stoichiometry

JEE Advanced 2020 — Paper 2 — Question 20

An acidified solution of potassium chromate was layered with an equal volume of amyl alcohol. When it was shaken after the addition of 1 mL of $3 \% \mathrm{H}_{2} \mathrm{O}_{2}$ , a blue alcohol layer was obtained. The blue color is due to the formation of a chromium (VI) compound ' $\mathbf{X}$ '. What is the number of oxygen atoms bonded to chromium through only single bonds in a molecule of $\mathbf{X}$ ?

Answer: 4

Numerical answer — enter this value.

Step-by-step solution

$\mathrm{CrO}_{4}^{2-} \underset{\mathrm{OH}^{-}}{\stackrel{\mathrm{H}^{+}}{\rightleftharpoons}} \mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}$

$\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}+\mathrm{H}_{2} \mathrm{O}+\mathrm{H}^{+} \longrightarrow \underset{\text { Chromium peroxide }}{\mathrm{CrO}_{5}}$

So, number of oxygen atoms attached to Cr through single bond $=4$

Answer key and solution verified before publishing.

Practise Some Basic Concepts of Chemistry (Mole Concept) + Stoichiometry

Start with this question, then two more from the same chapter — with a tutor that explains every step. Free.

Solve a similar one free

Exam: JEE Advanced 2020
Paper: Paper 2
Subject: Chemistry
Chapter: Some Basic Concepts of Chemistry (Mole Concept) + Stoichiometry
Topic: Other Miscellaneous Reactions and Related Problems