Strongest Acid among the Given Compounds

The given compounds are:

1. HCOOH (Formic acid)
2. CH3CH2CH(Cl)COOH (3-chlorobutyric acid)
3. ClCH2CH2CH2COOH (4-chlorobutyric acid)
4. CH3COOH (Acetic acid)

To determine the strongest acid among these compounds, we need to compare their acidic strength based on their dissociation constant (Ka) values.

Explanation

1. HCOOH (Formic acid)

Ka value of Formic acid is 1.77 x 10^-4. It is a weak acid and thus will not be the strongest acid among the given compounds.

2. CH3CH2CH(Cl)COOH (3-chlorobutyric acid)

3. ClCH2CH2CH2COOH (4-chlorobutyric acid)

These two compounds have similar structures but differ in the position of the chlorine atom. Both are stronger acids than formic acid due to the presence of the electron-withdrawing chlorine atom. However, 4-chlorobutyric acid has a lower pKa value (2.86) than 3-chlorobutyric acid (3.03), making it a stronger acid. Hence, 4-chlorobutyric acid is the strongest acid among these two compounds.

4. CH3COOH (Acetic acid)

Acetic acid has a pKa value of 4.76, which is higher than the pKa values of the above compounds. Hence, it is a weaker acid than the above compounds.

Conclusion

Based on the above analysis, we can conclude that 4-chlorobutyric acid (ClCH2CH2CH2COOH) is the strongest acid among the given compounds.