Question

Write a balanced equation for the redox reactions occurring between: b) An aldehyde (RCHO) and chromic acid (H2CrO4) to form a carboxylic acid (RCO2H) and Cr 3+

Answer 1

$RCHO + CrO_4^2^- + H^+ \rightarrow RCOOH + Cr^2^+ + H_2O\\ \\ CrO_4^2^- + 8H^+ + 3e \rightarrow Cr^3^+ + H_2O\ \ \ \ \ /\cdot 2\\ RCHO + H_2O \rightarrow RCOOH + 2H^+ + 2e\ \ \ \ \ \ /\cdot 3\\ \\ 3RCHO + 2CrO_4^2^- + 10H^+ \rightarrow 3RCOOH + 2Cr^2^+ + 5H_2O$