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Ortho effect and solvent effects

54 questions on Ortho effect and solvent effects from the General Organic Chemistry II: Acids and Bases chapter: 10 NEET level, 22 JEE Main, 22 JEE Advanced. Each one opens with its answer and solution.

Practice this topic All General Organic Chemistry II: Acids and Bases topics

Which of the following acids has the lowest pK_a (strongest acid)? (pK_a: benzoic acid 4.20; 2-methylbenzoic acid 3.91; 3-methylbenzoic acid 4.27; 4-methylbenzo... NEET level
The ortho effect in substituted benzoic acids is mainly attributed to NEET level
Which is the weakest base in aqueous solution among aniline, 4-methylaniline, 3-methylaniline and 2-nitroaniline? NEET level
In aqueous solution the correct order of acidity of the alcohols is NEET level
Among NH3, CH3NH2, (CH3)2NH and (CH3)3N, which is the strongest base in the gas phase? NEET level
In water, HCl, HNO3 and HClO4 all appear to be equally strong acids. This is called NEET level
Given pK_a: benzoic acid 4.20, 4-nitrobenzoic acid 3.44, 3-nitrobenzoic acid 3.45, 2-nitrobenzoic acid 2.17. Which is the strongest acid, and why is it stronger... JEE Main level
Which is the strongest acid among benzoic acid (4.20), 4-methylbenzoic acid (4.37), 4-methoxybenzoic acid (4.47) and 2,6-dimethylbenzoic acid (3.25)? Choose the... JEE Main level
The pK_a values of the conjugate acids (in water) are: aniline 4.6, 4-nitroaniline 1.0, 3-nitroaniline 2.5, 2-nitroaniline -0.3. Which of these amines is the we... JEE Main level
Which of the following best explains why ortho-substituted anilines are generally weaker bases than aniline in aqueous solution? JEE Main level
Salicylic acid (2-hydroxybenzoic acid, pK_a = 2.97) is a much stronger acid than 4-hydroxybenzoic acid (pK_a = 4.58). The best explanation is JEE Main level
The pK_a of acetic acid is 4.76 in water but about 12.3 in dimethyl sulfoxide (DMSO). The main reason is that JEE Main level
In the gas phase, which of the following alcohols is the most acidic? JEE Main level
In aqueous solution, which is the strongest base among NH3 (conjugate acid pK_a 9.25), C6H5NH2 (4.6), (CH3)3N (9.8) and (CH3)2NH (10.7)? JEE Main level
Assertion (A): 2-Methylbenzoic acid is a stronger acid than 4-methylbenzoic acid. Reason (R): An ortho substituent forces the COOH group out of the plane of the... JEE Main level
Which of the following acids are stronger than benzoic acid (pK_a 4.20)? JEE Main level
Trimethylamine is the strongest base among the methylamines in the gas phase, but in water it is weaker than CH3NH2 (pK_a of conjugate acids: 9.8 against 10.6).... JEE Main level
pK_a of benzoic acid is 4.20 and that of 2-nitrobenzoic acid is 2.17. How many times larger is K_a of 2-nitrobenzoic acid than K_a of benzoic acid? Give the ans... JEE Advanced level
Which statements are correct? (pK_a: benzoic acid 4.20, 4-chlorobenzoic acid 3.98, 2-chlorobenzoic acid 2.94; conjugate acids of amines: aniline 4.6, 2-nitroani... JEE Advanced level
Which of the following statements about 2,6-dimethylbenzoic acid is correct? JEE Advanced level
Salicylic acid is treated with excess aqueous NaHCO3. The first pK_a (carboxylic acid) is 2.97 and the second (phenolic OH in the salicylate anion, which is int... JEE Advanced level
Which statements are correct? (pK_a: benzoic acid 4.20, salicylic acid 2.97, 4-hydroxybenzoic acid 4.58.) JEE Advanced level
For the equilibrium 2-O2N-C6H4-NH2 + C6H5NH3+ <=> 2-O2N-C6H4-NH3+ + C6H5NH2 in water, the conjugate acids have pK_a of -0.3 (2-nitroanilinium) and 4.6 (aniliniu... JEE Advanced level
Which statements about alcohol acidity are correct? JEE Advanced level
Which statements about amine basicity are correct? (pK_a of conjugate acids in water: CH3NH3+ 10.6, (CH3)2NH2+ 10.7, (CH3)3NH+ 9.8, C6H5NH3+ 4.6.) JEE Advanced level
An ether solution contains benzoic acid (pK_a 4.20), 4-nitrophenol (7.15), 4-methylphenol (10.2) and toluene. It is extracted successively with aqueous NaHCO3 (... JEE Advanced level
Using pK_a values (acetic acid 4.76, benzoic acid 4.20, 2-nitrobenzoic acid 2.17, phenol 10.0, water 15.7), which of the following equilibria lies predominantly... JEE Advanced level
Among the following alcohols, which is the weakest acid in aqueous solution? NEET level
In water, HCl and HNO3 appear to be equally strong acids. This levelling effect occurs because NEET level
Which of the following is a stronger acid than benzoic acid because of the ortho effect? NEET level
In the gas phase, which of the following is the strongest base? NEET level
In the gas phase, the correct order of acidity of the alcohols is JEE Main level
Sodium amide, NaNH2, is dissolved in water. The strongest base actually present in the solution is JEE Main level
Carboxylic acids and phenols are far weaker acids in dimethyl sulfoxide (DMSO) than in water. The best explanation is that JEE Main level
Benzoic acid has pKa 4.20, 2-nitrobenzoic acid 2.17 and 4-nitrobenzoic acid 3.44 in water. Which sequence correctly gives decreasing acid strength, and its main... JEE Main level
In water, the pKa values are benzoic acid 4.20, 2-chlorobenzoic acid 2.94, 4-chlorobenzoic acid 3.98 and 4-methoxybenzoic acid 4.47. The strongest acid owes its... JEE Main level
In aqueous solution the pKa values of the conjugate acids are: aniline 4.6, 3-nitroaniline 2.5, 4-nitroaniline 1.0, 2-nitroaniline -0.3. The weakest base in aqu... JEE Main level
In water, tert-butyl alcohol (pKa about 18) is a weaker acid than methanol (pKa about 15.5). The best explanation is that JEE Main level
In the gas phase, tert-butyl alcohol is a stronger acid than methanol. This is best explained by JEE Main level
4-Nitrophenol is much more soluble in water than 2-nitrophenol. This is because JEE Main level
Perchloric acid, HClO4, and hydrochloric acid, HCl, cannot be distinguished by strength in water, but can be distinguished in glacial acetic acid. The reason is... JEE Main level
2,6-Dimethylbenzoic acid (pKa 3.25) is a considerably stronger acid than 4-methylbenzoic acid (pKa 4.37) in water. The best explanation is that JEE Main level
The pKa values in water are 3.25 for 2,6-dimethylbenzoic acid and 4.37 for 4-methylbenzoic acid. The value of K_a(2,6-dimethyl)/K_a(4-methyl) is closest to JEE Advanced level
Assertion (A): 2,6-Dimethylbenzoic acid is a stronger acid than 4-methylbenzoic acid. Reason (R): The two methyl groups stabilise the carboxylate ion by their e... JEE Advanced level
Phenol has pKa 10.0 in water and 18.0 in DMSO; 4-nitrophenol has pKa 7.15 in water and 10.8 in DMSO. The 4-nitro group increases acidity by 2.85 pKa units in wa... JEE Advanced level
50.0 mL of 0.100 M HClO4 and 50.0 mL of 0.300 M HNO3 are mixed in water. Treating both as completely ionised (levelled to H3O+), the pH of the mixture is JEE Advanced level
Salicylic acid (2-hydroxybenzoic acid) has pK_a1=2.97 for the COOH and pK_a2=13.6 for the phenolic OH, whereas 4-hydroxybenzoic acid has pK_a1=4.54. A single ex... JEE Advanced level
Methylamine and trimethylamine have gas-phase proton affinities of 899 and 942 kJ/mol respectively, so trimethylamine is the stronger base in the gas phase. In ... JEE Advanced level
Acetic acid has pKa 4.76 in water and 12.3 in DMSO. By what factor is K_a in water larger than K_a in DMSO? JEE Advanced level
Which of the following statements about alcohols are correct? JEE Advanced level
Which of the following statements are correct? JEE Advanced level
Which of the following statements about solvent effects are correct? JEE Advanced level
Which of the following statements about amine basicity are correct? (The conjugate-acid pKa values in water are: CH3NH3+ 10.6, NH4+ 9.25, (CH3)3NH+ 9.8, C6H5NH3... JEE Advanced level
Which of the following statements are correct? JEE Advanced level