Question

According to Bronsted-Lowry concept, the relative strengths of the bases $C{H_3}CO{O^ - },O{H^ - }$ and \[C{l^ - }\] are in the order:
A. $O{H^ - } > C{H_3}CO{O^ - } > C{l^ - }$
B. $C{l^ - } > O{H^ - } > C{H_3}CO{O^ - }$
C. $C{H_3}CO{O^ - } > O{H^ - } > C{l^ - }$
D. $O{H^ - } > C{l^ - } > C{H_3}CO{O^ - }$

Answer 1

Hint: The most basic principle of this theory is that when an acid and a base reacts with each other, the acid forms the conjugate base and reversely, the base forms its conjugate acid by the exchange of an electron or a proton (the cation of hydrogen formed with the loss of an electron, ${H^ + }$ ).

Complete step by step answer: According to the Bronsted-Lowry concept, whenever an acid reacts with a base, it undergoes a neutralization reaction to form salt and water. The reaction is as:
$Acid + Base \to Salt + {H_2}O$
The three ions given in the question are: $O{H^ - },C{l^ - },C{H_3}CO{O^ - }$
According to Lowry-Bronsted theory, a strong acid forms a weak conjugate base and a weak acid forms a strong conjugate base. Thus, we can determine the strength of the bases of the ions by determining the strength of their acids and then reversing the order of the strength of the acids.
Now, let us determine the acids of the corresponding conjugate bases.
$O{H^ - } + {H^ + } \to {H_2}O$
$C{l^ - } + {H^ + } \to HCl$
$C{H_3}CO{O^ - } + {H^ + } \to C{H_3}COOH$
In the above acids formed, the relative order of strength of the acids is:
$HCl > C{H_3}COOH > {H_2}O$
This order is determined by determining their $pH$ and from this we find out that hydrochloric acid is a strong acid and acetic acid is a weak acid. Water is a neutral compound but has a $pH$slightly greater than 7.
Thus, the correct option is A. $O{H^ - } > C{H_3}CO{O^ - } > C{l^ - }$.

Note: Water acts as an amphoteric compound, which means it can act as both as a Bronsted-Lowry acid and a Bronsted-Lowry base. Strong acids and bases have a complete ionization or $100\% $ degree of dissociation whereas weak acids and weak bases have a degree of dissociation less than $100\% $.