A pink-colored cobalt complex, denoted as (X), exists in aqueous solution. Upon reacting with concentrated HCl, it forms a deep blue-colored complex (Y). What are the identities of (X) and (Y), and what is the geometry of complex (Y), denoted as (Z)?
1. \(\left[\mathrm{Co}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+},\left[\mathrm{CoCl}_6\right]^{3-}, \text {Octahedral} \)
2. \(\left[\mathrm{Co}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+},\left[\mathrm{CoCl}_4\right]^{2-}, \text {Tetrahedral} \)
3. \(\left[\mathrm{Co}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+},\left[\mathrm{CoCl}_4\right]^{2-}, \text {Tetrahedral } \)
4. \(\left[\mathrm{Co}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+},\left[\mathrm{CoCl}_6\right]^{3-}, \text {Octahedral} \)