Question

Which chromium compound is widely used in training of leather?
A. $C{r_2}{O_3}$
B. $Cr{O_2}C{l_2}$
C. $CrC{l_3}$
D. ${K_2}S{O_4}.C{r_2}{(S{O_4})_3}.24{H_2}O$

Answer 1

Hint: The tanning of leather process can be automated and finished in a day, and the chrome ions displacing the water and binding with the collagen are much smaller than vegetable tanning molecules. This generally makes chrome tanned leather tanned leather thinner and softer than vegetable tanned leather.

Complete step by step answer:
The tanning of leather creates toxic wastewater that has detrimental environmental impact, Chrome tanned products neither wear well nor lasts very long and can crack after a few months of use. Chrome tanned products don't appear very natural and often carry a chemical smell.
Chromium is used in leather manufacturing and can be oxidized from the trivalent to the hexavalent state, which causes environmental concerns. The influence of Cr (III) from tanning, deacidification pH, chrome retaining and vegetable retaining on the formation of Cr (VI) in leather was analyzed by comparing natural and aged samples.
Chrome alum is useful for the tanning of leather, it stabilizes the leather by cross linking collagen fibers within the leather. Chromium alum ${K_2}S{O_4}.C{r_2}{(S{O_4})_3}.24{H_2}O$ is useful for tanning of leather. It is double sulphate of chromium.

That’s why option (D) is the correct answer.

Note:The chromium salt used in the tanning and chrome retaining was basic chromium sulfate with \[26\% \] chromium oxide and a basicity of \[33\% \] Schlemmer. During the tanning and wet finishing process, the base oils and ordinary commercial preparations available in the leather industry were used. Only analytical grade chemicals were used in analyses.