Which is mismatched regarding the formula?

Options

A. Epsom salt `-MgSO_(4).7H_(2)O`
B. Baryte-`BeSO_(4)`
C. Copper pyrite-`CuFeS_(2)`
D. Galena`-PbS`

Answer

To determine which option is mismatched regarding the formula, we will analyze each option provided.

### Step 1: Analyze the first option
- **Option 1:** Epsom salt is MgSO4.7H2O.
- Epsom salt is indeed magnesium sulfate heptahydrate, which has the correct formula of MgSO4.7H2O.
- **Conclusion:** This option is correct.

### Step 2: Analyze the second option
- **Option 2:** Barite is BeSO4.
- Barite is actually barium sulfate, which has the formula BaSO4, not BeSO4 (which would be beryllium sulfate).
- **Conclusion:** This option is incorrect and mismatched.

### Step 3: Analyze the third option
- **Option 3:** Copper pyrite is CuFeS2.
- Copper pyrite, also known as chalcopyrite, has the correct formula CuFeS2.
- **Conclusion:** This option is correct.

### Step 4: Analyze the fourth option
- **Option 4:** Galena is PbS.
- Galena, also known as lead glance, has the correct formula PbS.
- **Conclusion:** This option is correct.

### Final Conclusion
After analyzing all the options, the mismatched option regarding the formula is:
- **Option 2:** Barite is incorrectly stated as BeSO4 instead of BaSO4.