question_answer 1)

It has been found that the pH of a 0.01 M solution of organic acid is 4.15. Calculate the concentration of the onion, the ionisation constant of the acid and its\[p{{K}_{a}}\].

Answer:

Let the acid is HA. \[\underset{\begin{smallmatrix} t=0 \\ {{t}_{eq}} \end{smallmatrix}}{\overset{{}}{\mathop{{}}}}\,\,\,\,\,\underset{\begin{smallmatrix} C \\ C-C\alpha \end{smallmatrix}}{\mathop{HA}}\,\rightleftharpoons \underset{\begin{smallmatrix} 0 \\ C\alpha \end{smallmatrix}}{\mathop{{{H}^{+}}}}\,+\underset{\begin{smallmatrix} 0 \\ C\alpha \end{smallmatrix}}{\mathop{{{A}^{-}}}}\,\] \[{{K}_{a}}=\frac{C\alpha \times C\alpha }{C-C\alpha }=\frac{C{{\alpha }^{2}}}{1-\alpha }\] \[\alpha