Which pair of species has the same percentage compostion?

Options

A. `C_(6) H_(12)O_(6)` and `C_(12) H_(22) O_(11)`
B. `C_(6) H_(12)O_(6)` and `CH_(3) COOH`
C. `C_(2) H_(5) OH` and `CH_(3) COOH`
D. `C_(12) H_(22) O_(11)` and `HCOOH_(3)`

Explanation

To determine which pair of species has the same percentage composition, we need to find the empirical formulas of the given compounds. The empirical formula represents the simplest whole-number ratio of the elements in a compound. If two compounds have the same empirical formula, they will have the same percentage composition.

### Step-by-Step Solution:

1. **Identify the Compounds**:
Let's denote the four options as A, B, C, and D. We need to analyze the molecular formulas of each compound.

2. **Calculate the Empirical Formula**:
- For each compound, we will find the empirical formula by determining the ratio of the number of atoms of each element in the compound.
- The empirical formula can be calculated by dividing the number of atoms of each element by the greatest common divisor.

3. **Compare Empirical Formulas**:
- Once we have the empirical formulas for all options, we will compare them.
- If two compounds have the same empirical formula, they will have the same percentage composition.

4. **Identify the Correct Pair**:
- After comparing the empirical formulas, we will identify which pair of compounds has the same empirical formula.

### Example Calculation:

Let's say we have the following compounds:
- A: C6H12O6
- B: C2H4O2
- C: C3H6O3
- D: C4H8O2

Now, let's calculate the empirical formulas:

- **For A (C6H12O6)**:
- The ratio of C:H:O = 6:12:6
- Dividing by 6 gives us the empirical formula: C1H2O1 or simply CH2O.

- **For B (C2H4O2)**:
- The ratio of C:H:O = 2:4:2
- Dividing by 2 gives us the empirical formula: C1H2O1 or simply CH2O.

- **For C (C3H6O3)**:
- The ratio of C:H:O = 3:6:3
- Dividing by 3 gives us the empirical formula: C1H2O1 or simply CH2O.

- **For D (C4H8O2)**:
- The ratio of C:H:O = 4:8:2
- Dividing by 2 gives us the empirical formula: C2H4O1 or simply C2H4O.

### Conclusion:
From our calculations, we see that compounds A, B, and C all have the same empirical formula (CH2O), while compound D has a different empirical formula (C2H4O). Thus, the correct answer is that compounds A (C6H12O6), B (C2H4O2), and C (C3H6O3) have the same percentage composition.

### Final Answer:
The pair of species with the same percentage composition is A (C6H12O6) and B (C2H4O2).