How many of these acids have `S-S` bonds?
`H_(2)S_(2)O_(3), H_(2)S_(2)O_(6), H_(2)S_(2)O_(7), H_(2)S_(2)O_(8), H_(2)SO_(5), H_(2)S_(n+2)O_(6)`.
(polythionic acid).

Answer

To determine how many of the given acids have sulfur-sulfur (S-S) bonds, we will analyze the structures of each acid one by one.

### Step-by-Step Solution:

1. **Identify the Acids**: The acids given are:
- \( H_2S_2O_3 \)
- \( H_2S_2O_6 \)
- \( H_2S_2O_7 \)
- \( H_2S_2O_8 \)
- \( H_2SO_5 \)
- \( H_2S_{n+2}O_6 \) (where \( n \) is a variable indicating the number of sulfur atoms)

2. **Analyze Each Acid for S-S Bonds**:
- **For \( H_2S_2O_3 \)**: The structure indicates that there is a sulfur-sulfur bond present.
- **For \( H_2S_2O_6 \)**: This acid also contains a sulfur-sulfur bond.
- **For \( H_2S_2O_7 \)**: In this structure, there is no sulfur-sulfur bond; it only has S-O bonds.
- **For \( H_2S_2O_8 \)**: Similar to \( H_2S_2O_7 \), this acid does not have a sulfur-sulfur bond.
- **For \( H_2SO_5 \)**: This acid does not contain a sulfur-sulfur bond; it has S-O bonds.
- **For \( H_2S_{n+2}O_6 \)**: This is a polythionic acid, and since it has more than two sulfur atoms, it will have at least one S-S bond.

3. **Count the Acids with S-S Bonds**:
- From the analysis:
- \( H_2S_2O_3 \): 1 S-S bond
- \( H_2S_2O_6 \): 1 S-S bond
- \( H_2S_{n+2}O_6 \): 1 or more S-S bonds (depending on the value of \( n \))
- Therefore, we have:
- \( H_2S_2O_3 \): Yes
- \( H_2S_2O_6 \): Yes
- \( H_2S_2O_7 \): No
- \( H_2S_2O_8 \): No
- \( H_2SO_5 \): No
- \( H_2S_{n+2}O_6 \): Yes (at least one S-S bond)

4. **Final Count**:
- Total acids with S-S bonds = 3 (from \( H_2S_2O_3 \), \( H_2S_2O_6 \), and \( H_2S_{n+2}O_6 \)).

### Conclusion:
The total number of acids that have S-S bonds is **3**.