The phenyl group electron-donating or electron-withdrawing

Assignment Help Chemistry

Reference no: EM13170979

The relative acidities of carboxylic acids (and, by inference, the stabilities of their carboxylate ions) have been used to compare the electron-donating and electron-withdrawing properties of substituents. These studies are particularly valuable to distinguish between inductive and resonance effects on the stabilities of compounds and ions. Some examples:

a. The phenyl group is a mild ortho, para director in electrophilic aromatic substitution. Is the phenyl group electron-donating or electron-withdrawing in EAS?

b. The pKa of phenylacetic acid is 4.31, showing that phenylacetic acid is a stronger acid than acetic acid. Is the phenyl group electron-donating or electron-withdrawing in the ionization of phenylacetic acid? How can you resolve the apparent contradiction?

c. 4-methoxybenzoic acid is a weaker acid than benzoic acid, but methoxyacetic acid is a stronger acid than acetic acid. Explain this apparent contradiction.

d. Methyl groups are usually electron-donating and propanoic acid is a weaker acid than acetic acid. Yet 2,6-dimethylbenzoinc acid is a stronger acid than benzoic acid, but 2,6-dimethylphenol is a weaker acid than phenol. Explain these confusing experimental results.

Reference no: EM13170979

Questions Cloud

What is the mole ratio of benzene to n-octane in the vapor : What is the mole ratio of benzene to n-octane in the vapor above a solution of 20.0% benzene and 80% n-octane by mass at 25C? The vapor pressures of n-octane and benzene at 25 c are 11 torr and 95 torr, respectively

State celsius is allowed to expand into an evacuated vessel : Celsius is allowed to expand into an evacuated vessel of 2.50 L volume. Does the gas do work? Explain

What is the boiling point for bromine : If the heat of vaporization for Br2 is 29.6 kJ/mol and ΔS° for the vaporization is 88.9 J/mol⋅K, what is the boiling point for bromine?

What products might come out of our r&d activities : What products might come out of our R&D activities. This is a quote from an R&D manager who was asked to justify investment in a major research project based on its expected net present value.

The phenyl group electron-donating or electron-withdrawing : 4-methoxybenzoic acid is a weaker acid than benzoic acid, but methoxyacetic acid is a stronger acid than acetic acid. Explain this apparent contradiction.

What mass of p2o5 can be produced : If all of the phosphorus in a 3.00 g sample of MgNH4PO4 is extracted and used to make diphosphorus pentaoxide, what mass of P2O5 can be produced?

What is the new pressure in the bicycle tire : A bicycle tire is filled with air to a pressure of 720 torr at a temperature of 19 degrees Celsius. Riding the bike on asphalt on a hot day increases the temperature of the tire to 58 degrees Celsius.

Compute ecell and state whether the reaction is spontaneous : Balance the following skeleton reaction, calculate Ecell, and state whether the reaction is spontaneous:

What is the mass of the sample of water : The temperature of a sample of water increases by 6.5 degrees Celsius when 8.5 kilo Joules are applied. The specific heat of liquid water is 4.18 Joules per gram x degrees Celcius. What is the mass of the sample of water?

User Account

All Pages