15) For complete oxidation, 1 mole of an organic compound requires the maximum amount of [tex]$O_2$[/tex] gas. What could be the formula of the compound?

A. [tex]$CH_3CHO$[/tex]
B. [tex][tex]$CH_3CH_2OH$[/tex][/tex]
C. [tex]$CH_3CH_3$[/tex]
D. [tex]$CH_3CO_2H$[/tex]



Answer :

To determine which organic compound requires the maximum amount of [tex]\( O_2 \)[/tex] gas for complete oxidation, we will look at each compound and calculate the moles of [tex]\( O_2 \)[/tex] required. Here are the four compounds:

1. [tex]\( CH_3CHO \)[/tex] (Acetaldehyde):
- Number of Carbon atoms (C): 2
- Number of Hydrogen atoms (H): 4
- Number of Oxygen atoms (O): 1

2. [tex]\( CH_3CH_3 \)[/tex] (Ethane):
- Number of Carbon atoms (C): 2
- Number of Hydrogen atoms (H): 6
- Number of Oxygen atoms (O): 0

3. [tex]\( CH_3CH_2OH \)[/tex] (Ethanol):
- Number of Carbon atoms (C): 2
- Number of Hydrogen atoms (H): 6
- Number of Oxygen atoms (O): 1

4. [tex]\( CH_3CO_2H \)[/tex] (Acetic Acid):
- Number of Carbon atoms (C): 2
- Number of Hydrogen atoms (H): 4
- Number of Oxygen atoms (O): 2

The general formula for calculating the amount of [tex]\( O_2 \)[/tex] needed for complete oxidation of a compound [tex]\( C_xH_yO_z \)[/tex] is:
[tex]\[ \text{O}_2 \text{ needed} = x + \frac{y}{4} - \frac{z}{2} \][/tex]

Let's calculate the moles of [tex]\( O_2 \)[/tex] needed for each compound:

1. [tex]\( CH_3CHO \)[/tex]:
[tex]\[ x = 2 \][/tex]
[tex]\[ y = 4 \][/tex]
[tex]\[ z = 1 \][/tex]
[tex]\[ \text{O}_2 \text{ needed} = 2 + \frac{4}{4} - \frac{1}{2} = 2 + 1 - 0.5 = 2.5 \][/tex]

2. [tex]\( CH_3CH_3 \)[/tex]:
[tex]\[ x = 2 \][/tex]
[tex]\[ y = 6 \][/tex]
[tex]\[ z = 0 \][/tex]
[tex]\[ \text{O}_2 \text{ needed} = 2 + \frac{6}{4} - \frac{0}{2} = 2 + \frac{3}{2} = 3.5 \][/tex]

3. [tex]\( CH_3CH_2OH \)[/tex]:
[tex]\[ x = 2 \][/tex]
[tex]\[ y = 6 \][/tex]
[tex]\[ z = 1 \][/tex]
[tex]\[ \text{O}_2 \text{ needed} = 2 + \frac{6}{4} - \frac{1}{2} = 2 + 1.5 - 0.5 = 3.0 \][/tex]

4. [tex]\( CH_3CO_2H \)[/tex]:
[tex]\[ x = 2 \][/tex]
[tex]\[ y = 4 \][/tex]
[tex]\[ z = 2 \][/tex]
[tex]\[ \text{O}_2 \text{ needed} = 2 + \frac{4}{4} - \frac{2}{2} = 2 + 1 - 1 = 2 \][/tex]

After performing the calculations, we find the amount of [tex]\( O_2 \)[/tex] required for each compound:
- [tex]\( CH_3CHO \)[/tex]: 2.5 moles
- [tex]\( CH_3CH_3 \)[/tex]: 3.5 moles
- [tex]\( CH_3CH_2OH \)[/tex]: 3.0 moles
- [tex]\( CH_3CO_2H \)[/tex]: 2.0 moles

The compound that requires the maximum amount of [tex]\( O_2 \)[/tex] for complete oxidation is [tex]\( CH_3CH_3 \)[/tex] (Ethane), which requires 3.5 moles of [tex]\( O_2 \)[/tex].

Thus, the answer is:
e. [tex]\( CH_3CH_3 \)[/tex]