Question: Which of the following is the conjugate base of \[{\left[ {{C_2}{H_5}N{H_3}} \right]^ + }\] A. \[...

Question

Which of the following is the conjugate base of ${\left[ {{C_2}{H_5}N{H_3}} \right]^ + }$
A. ${C_2}{H_5}N{H_2}$
B. ${\left[ {{C_2}{N^ + }{H_4}\left( {OH} \right)} \right]^ - }$
C. ${\left[ {{C_2}{H_2}NH} \right]^ - }$
D.None of theses

Answer 1

Solution

According to the Brosted-lowry acid-base theory, the conjugate base is formed after donation of hydrogen ion from an acid. i.e. the negatively charged ion of acid is the conjugate base of that particular acid.

Complete step by step answer:
The strength of acid plays a vital role in the formation of the conjugate base of that acid. if an acid donates hydrogen ion, then its conjugate base accepts hydrogen ion. Now higher the acidity of the acid lower will be the basicity of the conjugate base and vice-versa.
Therefore, for a strong acid, its corresponding conjugate base is weak. And for weak acid, its corresponding conjugate base is strong.
In the case of ${\left[ {{C_2}{H_5}N{H_3}} \right]^ + }$ which is an acid can be formed from its corresponding base by abstracting hydrogen ion.

The correct answer is, A.

Additional information:
The strength of acid plays a vital role in the formation of the conjugate base of that acid. if an acid donates hydrogen ion, then its conjugate base accepts hydrogen ion. Now higher the acidity of the acid lower will be the basicity of the conjugate base and vice-versa.
Therefore, for a strong acid its corresponding conjugate base is a weak base. And for weak acid, its corresponding conjugate base is strong.
Now the strength of acidity depends upon the different factors, some of those are, for carboxylic acids electron-withdrawing effect increases the acidity. On the other hand, electronegative sp carbon of acetylene shows acidity. But carboxylic acids are more strong acid than acetylene.

Note: Remember that the higher the acidity of the acid lower will be the basicity of the conjugate base and vice-versa. For a strong acid its corresponding conjugate base I weak base. And for weak acid, its corresponding conjugate base is strong. For carboxylic acids, the electron-withdrawing effect increases the acidity.