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 'X' . What is the number of oxygen atoms bonded to chromium through only single bonds in a molecule of \(\mathbf{X}\) ?

JEE Advanced · 2020 · 27 Sep 2020 · Paper 2 · d and f Block Elements

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% H_{2} O_{2}

, a blue alcohol layer was obtained. The blue color is due to the formation of a chromium (VI) compound 'X' . What is the number of oxygen atoms bonded to chromium through only single bonds in a molecule of

X

Answer: 4

Solution

The reaction is:

K_{2} CrO_{4} + H_{2} O_{2} Amyl alcohol (In acidic medium) CrO_{5}

The blue compound X is chromium pentoxide (

CrO_{5}

).

Structure of

CrO_{5}

: Chromium is bonded to:

1 oxygen via double bond (Cr=O)
4 oxygen atoms via single bonds (forming two peroxo bridges: -O-O-)

The number of oxygen atoms bonded to chromium through only single bonds = 4

JEE Advanced · 2020 · 27 Sep 2020 · Paper 2 · Integer answer

Practise more: all JEE Advanced PYQs on d and f Block Elements →

JEE Advanced · 2020 · 27 Sep 2020 · Paper 2 · d and f Block Elements

Solution

More JEE Advanced questions on d and f Block Elements