Which of the following Chromium Compound used in tanning of Leather?

\(K_2SO_4 Cr_2(SO_4)_3.24H_2O\)

The correct answer is option 3. \(K_2SO_4 Cr_2(SO_4)_3.24H_2O\).

This compound is also known as chrome alum, and it is a trivalent chromium compound. Trivalent chromium compounds are used in leather tanning because they form a strong bond with the proteins in the leather. This bond helps to preserve the leather and prevent it from rotting.

The other answer choices are incorrect. \(CrCl_3\) is a hexavalent chromium compound, which is not used in leather tanning.  \(CrO_2Cl_2\) is a chromium oxychloride, which is also not used in leather tanning. \(Cr_2O_3\) is chromium oxide, which is not used in leather tanning.