Question

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 1

We have to the find the number of oxygen atoms bounded to chromium through only single bonds in a molecule of X.

solution : chromate ion reacts with hydrogen peroxide in acidified solution gives chromium pentoxide which dissolves in amyl alcohol to give blue colour.

chemical reaction is written as ...

CrO₄²¯ + H₂O₂ + 2H⁺ ⇒CrO₅ ⇒amy alcohol ⇒blue colour

so, The compound X is chromium pentoxide.

structure of chromium pentoxide is shown in figure. it is clear that there are four single bond in a molecule of CrO₅.

Therefore 4 number of oxygen atoms bonded to chromium through only single bonds in a molecule of X.