Question

What is the product of the reaction?
$HCHO + {K_2}C{r_2}{O_7} + {H_2}S{O_4} \to ?$

Answer 1

The given question is an example of redox reaction where, Potassium Dichromate $({K_2}C{r_2}{O_7})$ act as an oxidizing agent and causes oxidation of Formaldehyde (HCHO) and under acidic conditions, the aldehyde is oxidized to a carboxylic acid.

Complete step by step answer:
Formaldehyde (HCHO) in the presence of Potassium Dichromate $({K_2}C{r_2}{O_7})$ undergoes oxidation reaction to give formic acid (HCOOH), Chromium (III) sulphate $(C{r_2}{(S{O_4})_3})$, Potassium sulphate $({K_2}S{O_4})$ and water $({H_2}O)$ as products.

$3HCHO + {K_2}C{r_2}{O_7} + 4{H_2}S{O_4} \to 3HCOOH + C{r_2}{(S{O_4})_3} + {K_2}S{O_4} + 4{H_2}O$

This is an oxidation-reduction (redox) reaction where HCHO is a reducing agent, ${K_2}C{r_2}{O_7}$ is an oxidizing agent.
Hence, the products of the above reaction are formic acid (HCOOH), Chromium (III) sulphate $(C{r_2}{(S{O_4})_3})$, Potassium sulphate $({K_2}S{O_4})$ and water $({H_2}O)$.

Note: It should be noted that under the acidic conditions, the aldehyde is oxidized to a carboxylic acid but under an alkaline condition, this couldn't be formed because it would react with the alkali and a salt is formed instead.
Formaldehyde (HCHO) is a colourless gas with a pungent odour. Potassium dichromate $({K_2}C{r_2}{O_7})$ is the most commonly used as an oxidising agent in various laboratory and industrial applications. It is used to oxidize alcohol. It converts primary alcohols into aldehydes and, under more forcing conditions, into carboxylic acids. Formic acid (HCOOH), also known as Methanolic acid is the simplest of the carboxylic acids. It is used in the processing of textiles and leather. Formic acid is made by the action of sulphuric acid upon sodium format, which is produced from carbon monoxide and sodium hydroxide.