Last lesson we calculated that propane has an energy of combustion of 2220 kilojoules per mole while hydrogen gas (rocket fuel)
has an energy of combustion of 286 kilojoules per mole. However, hydrogen gas has a much higher energy of combustion per gram than propane. Why is this? 
1 answer:
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CH_3 CH_2 Cl has two different types of hydrogen. On further chlorination they are being substituted by chlorine to give two isomeric dichlorides
The structures of the two chlorides are shown below.
Where Hb is replaced by Cl and Ha is replaced by Cl
The structures of the two chlorides are shown below.
Where Hb is replaced by Cl and Ha is replaced by Cl
Answer:
D. The electron-withdrawing fluorine atoms pull electron density from the oxygen in trifluoroacetate. The negative charge is more stabilized in trifluoroacetate by this effect.
Explanation:
The structures of trifluoroacetate and acetic acid are both shown in the image attached.
The trifluoroacetate anion (CF3CO2-), just like the acetate anion has in the middle, two oxygen atoms.
However, in the trifluoroacetate anion, there are also three electronegative fluorine atoms attached to the nearby carbon atom attached to the carbonyl, and these pull some electron density through the sigma bonding network away from the oxygen atoms, thereby spreading out the negative charge further. This effect, called the "inductive effect" stabilizes the anion formed,the trifouoroacetate anion is thus more stabilized than the acetate anion.
Hence, trifluoroacetic acid is a stronger acid than acetic acid, having a pKa of -0.18.
