Chemistry · Acids, Bases and Salts
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Which one f the following has the lowest pH?
- A
1 M HF
- B
1 M HCL
- C
1 m CH3COOH
- D
1 M NaOH
As we know that lower the pH, stronger the acid and greater the no of hydrogen ions in a solution. The acidity of an acid is measured by the ability to remove hydrogen ion.
HF is the weakest acid among all of these due to greater electronegativity difference between hydrogen ion and fluorine than chlorine. Therefore, HF does not disassociate readily in water thus having higher PH than acetic acid and hydrochloric acid due to negligible ability to remove hydrogen atom.
HCl is comparatively a stronger acid than HF but weaker acid than acetic acid. The Chlorine atom in HCl has greater electronegativity towards hydrogen ion due to greater electronegativity difference between chlorine and hydrogen ion. Therefore, HCl does not readily disassociates in water and has greater ph than acetic acid but lower than HF.
Acetic acid is the strongest acid among all of these as it readily disassociates in water giving hydrogen ions. Therefore, lower the Ph, greater the no of hydrogen ions and stronger the acid. It disassociates into acetate ion and hydrogen ion. The acetate ion thus produced is a conjugate base and is stable enough due to resonance phenomena of carboxyl group between two oxygen atoms.
Tagged under Chemistry · Acids, Bases and Salts · 2008