What is the effect of increasing pH on a K$_2$Cr$_2$O$_7$ solution?

CBSE Class 12 · 2003 · All India · d and f Block ElementsVery Short Answer

What is the effect of increasing pH on a K

_{2}

_{2}

_{7}

solution?

Answer: The orange dichromate changes to yellow chromate: Cr₂O₇²⁻ + 2OH⁻ → 2CrO₄²⁻ + H₂O.

Raising the pH (adding alkali) converts dichromate to chromate:

C r_{2} O_{7}^{2 -} (orange) + 2O H^{-} \to 2Cr O_{4}^{2 -} (yellow) + H_{2} O

The solution turns from orange to yellow; lowering the pH reverses the change.

CBSE Class 12 Board · 2003 · All India · Subjective