The masses of carbon, hydrogen and oxygen in ann organic compound are in the ratio 6:1:8 respectively. Which of the following pairs of formulae correspond to above information?

Options

A. `CH_(3)O and CH_(3)CHO`
B. `CH_(2)O and C_(3)H_(6)O`
C. `C_(3)H_(6)O and C_(2)H_(6)O_(2)`
D. `C_(3)H_(6)O_(3) and HCHO`

Explanation

To solve the problem, we need to determine which of the given pairs of formulae correspond to the mass ratio of carbon, hydrogen, and oxygen in the organic compound, which is given as 6:1:8.

### Step-by-Step Solution:

1. **Understanding the Mass Ratio**:
The mass ratio of carbon (C), hydrogen (H), and oxygen (O) is given as 6:1:8. This means that for every 6 grams of carbon, there is 1 gram of hydrogen and 8 grams of oxygen.

2. **Calculating Molar Masses**:
- The atomic mass of carbon (C) = 12 g/mol
- The atomic mass of hydrogen (H) = 1 g/mol
- The atomic mass of oxygen (O) = 16 g/mol

3. **Finding the Total Mass**:
To compare the ratios, we can convert the mass ratio into a molar ratio. The total mass for the ratio 6:1:8 is:
\[ 6 + 1 + 8 = 15 \text{ grams} \]

4. **Converting Mass Ratio to Moles**:
Now we convert the mass ratio to moles:
- Moles of C = \( \frac{6 \text{ g}}{12 \text{ g/mol}} = 0.5 \text{ mol} \)
- Moles of H = \( \frac{1 \text{ g}}{1 \text{ g/mol}} = 1 \text{ mol} \)
- Moles of O = \( \frac{8 \text{ g}}{16 \text{ g/mol}} = 0.5 \text{ mol} \)

5. **Simplifying the Molar Ratio**:
The molar ratio of C:H:O is:
\[ 0.5 : 1 : 0.5 \]
To simplify, we can multiply each part by 2:
\[ 1 : 2 : 1 \]

6. **Analyzing the Given Options**:
We need to check each option to see if they can be expressed in the same ratio of 1:2:1.

- **Option A**: CH3O and C2H4O
- CH3O: C = 12 g, H = 3 g, O = 16 g → Ratio = 12:3:16 (not matching)
- C2H4O: C = 24 g, H = 8 g, O = 16 g → Ratio = 24:8:16 (not matching)

- **Option B**: CH2O and C3H6O
- CH2O: C = 12 g, H = 2 g, O = 16 g → Ratio = 12:2:16 (not matching)
- C3H6O: C = 36 g, H = 6 g, O = 16 g → Ratio = 36:6:16 (not matching)

- **Option C**: C3H6O and C2H6O2
- C3H6O: C = 36 g, H = 6 g, O = 16 g → Ratio = 36:6:16 (not matching)
- C2H6O2: C = 24 g, H = 6 g, O = 32 g → Ratio = 24:6:32 (not matching)

- **Option D**: C3H6O3 and CH2O
- C3H6O3: C = 36 g, H = 6 g, O = 48 g → Ratio = 36:6:48 → Simplifies to 6:1:8 (matching)
- CH2O: C = 12 g, H = 2 g, O = 16 g → Ratio = 12:2:16 (not matching)

7. **Conclusion**:
After analyzing all options, **Option D** (C3H6O3 and CH2O) corresponds to the mass ratio of 6:1:8.