A) 3.4
B) 4.8
C) 1.6
D) 2.6
Correct Answer: D
Solution :
| [d] \[C{{H}_{3}}COOH\,C{{H}_{3}}CO{{O}^{-}}+\,{{H}^{+}}\] |
| \[\begin{matrix} \text{Initial}\,\text{conce}\text{.}\,\,\,\frac{1}{10} & 0 & 0 \\ \text{After}\,t\,\text{time}\,\,\,\,\,\,\frac{1}{10}-\frac{1}{10}\times \frac{1.0}{100} & \frac{1}{10}\times \frac{1.0}{100} & \frac{1}{10}\times \frac{1.0}{100} \\ \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,=0.1 & \,\,\,\,\,\,\,\,\,\,\,=0.001 & \,\,\,\,\,\,\,\,=0.001 \\ \end{matrix}\] |
| \[K=\frac{0.001\times 0.001}{0.1}\] |
| \[=1\times {{10}^{-5}}\] (i) |
| In case of seminormal solution |
| \[C{{H}_{3}}COOH\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,C{{H}_{3}}CO{{O}^{-}}\,\,\,\,\,+\,\,\,\,\,\,{{H}^{+}}\]\[\begin{matrix} \text{Initial}\,\text{conc}\text{.}\,\,\,\,\frac{1}{2} & 0 & 0 \\ \text{After}\,t\,\text{time}\,\,\frac{1}{2}-\frac{1}{2}\times \frac{x}{100} & \,\,\,\frac{1}{2}\times \frac{x}{100}\,\,\, & \frac{1}{2}\times \frac{x}{100} \\ \end{matrix}\] |
| \[=0.5\] [let solution is \[x%\] ionised] |
| \[K=\frac{{{\left( \frac{1}{2}\times \frac{x}{100} \right)}^{2}}}{0.5}\] |
| \[=\frac{{{x}^{2}}}{20000}\] (ii) |
| From Eqs (i) and (ii) |
| \[\frac{{{x}^{2}}}{20000}=1\times {{10}^{-5}}\] |
| \[x=0.447\] |
| \[[{{H}^{+}}]=\frac{1}{2}\times \frac{x}{100}\] |
| \[=\frac{1}{2}\times \frac{0.447}{100}=0.00224\] |
| \[pH=-\log \,[{{H}^{+}}]\] |
| \[=-\log \,[0.00224]=2.65\] |
You need to login to perform this action.
You will be redirected in
3 sec
