contestada

A buffered solution containing dissolved aniline, C 6 H 5 NH 2 , and aniline hydrochloride, C 6 H 5 NH 3 Cl , has a pH of 5.34 . A. Determine the concentration of C 6 H 5 NH 3 in the solution if the concentration of C 6 H 5 NH 2 is 0.245 M. The p K b of aniline is 9.13.

Respuesta :

Answer : The  concentration of [tex]C_6H_5NH_3^+[/tex] is, 0.0830 M

Explanation : Given,

[tex]pK_b=9.13[/tex]

Concentration of [tex]C_6H_5NH_2[/tex] = 0.245 M

pH = 5.34

First we have to calculate the value of pOH.

[tex]pH+pOH=14\\\\pOH=14-pH\\\\pOH=14-5.34\\\\pOH=8.66[/tex]

Now we have to calculate the concentration of [tex]C_6H_5NH_3^+[/tex]

Using Henderson Hesselbach equation :

[tex]pOH=pK_b+\log \frac{[Salt]}{[Base]}[/tex]

[tex]pOH=pK_b+\log \frac{[C_6H_5NH_3^+]}{[C_6H_5NH_2]}[/tex]

Now put all the given values in this expression, we get:

[tex]8.66=9.13+\log (\frac{[C_6H_5NH_3^+]}{0.245})[/tex]

[tex][C_6H_5NH_3^+]=0.0830M[/tex]

Therefore, the concentration of [tex]C_6H_5NH_3^+[/tex] is, 0.0830 M

Otras preguntas