2. Which of the following is the correct formula for Ammonium Dichromate. A. \( \mathrm{NH}_{4} \mathrm{Cr}_{2} \mathrm{O}_{7} \) B. \( \mathrm{NH}_{4}\left(\mathrm{Cr}_{2} \mathrm{O}_{7}\right)_{2} \) C. \( \left(\mathrm{NH}_{4}\right)_{2} \mathrm{Cr}_{2} \mathrm{O}_{7} \) D. \( \left(\mathrm{NH}_{4}\right)_{2} \mathrm{CrO}_{4} \)

To determine the correct formula for Ammonium Dichromate, we need to analyze the components of the compound: 1. **Ammonium Ion**: The ammonium ion is represented as \( \mathrm{NH}_{4}^{+} \). 2. **Dichromate Ion**: The dichromate ion is represented as \( \mathrm{Cr}_{2}\mathrm{O}_{7}^{2-} \). Since the ammonium ion has a charge of \( +1 \) and the dichromate ion has a charge of \( -2 \), we need two ammonium ions to balance the charge of one dichromate ion. Therefore, the formula for Ammonium Dichromate can be constructed as follows: - We need 2 ammonium ions: \( 2 \times \mathrm{NH}_{4}^{+} \) - We need 1 dichromate ion: \( \mathrm{Cr}_{2}\mathrm{O}_{7}^{2-} \) Putting this together, the formula becomes: \[ \left(\mathrm{NH}_{4}\right)_{2} \mathrm{Cr}_{2} \mathrm{O}_{7} \] Now, let's compare this with the options provided: A. \( \mathrm{NH}_{4} \mathrm{Cr}_{2} \mathrm{O}_{7} \) B. \( \mathrm{NH}_{4}\left(\mathrm{Cr}_{2} \mathrm{O}_{7}\right)_{2} \) C. \( \left(\mathrm{NH}_{4}\right)_{2} \mathrm{Cr}_{2} \mathrm{O}_{7} \) D. \( \left(\mathrm{NH}_{4}\right)_{2} \mathrm{CrO}_{4} \) The correct formula for Ammonium Dichromate is: **C. \( \left(\mathrm{NH}_{4}\right)_{2} \mathrm{Cr}_{2} \mathrm{O}_{7} \)**.