Ramendra C Mukerjee Solutions for Chapter: Miscellaneous Problems for Revision, Exercise 1: Exercise 1

A $0.288 \mathrm{g}$ sample of an unknown monoprotic organic acid is dissolved in water and titrated with a $0.115\mathrm{M}$ sodium hydroxide solution. After the addition of $17.54 \mathrm{mL}$ of base, a $\mathrm{pH}$ of $4.92$ is recorded. The equivalence point is reached when a total of $33.83 \mathrm{mL}$ of $\mathrm{NaOH}$ is added.

What is the molar mass of the organic acid?

A $0.288 \mathrm{g}$ sample of an unknown monoprotic organic acid is dissolved in water and titrated with a $0.115\mathrm{M}$ sodium hydroxide solution. After the addition of $17.54 \mathrm{mL}$ of base, a $\mathrm{pH}$ of $4.92$ is recorded. The equivalence point is reached when a total of $33.83 \mathrm{mL}$ of $\mathrm{NaOH}$ is added.

What is the $K_a$ value for the acid? The $K_a$ value could have been determined very easily if a $\mathrm{pH}$ measurement had been made after the addition of $16.92 \mathrm{mL}$ of $\mathrm{NaOH}$. Why?

In the following equilibrium ${\mathrm{N}}_2{\mathrm{O}}_4\left(\mathrm{g}\right)\rightleftharpoons 2{\mathrm{NO}}_2\left(\mathrm{g}\right)$

When $5$ mole of each are taken, the temperature is kept at $298 \mathrm{K}$. The total pressure was found to be $20$ bar. Given: $\Delta G_f^0\left({ \mathrm{N}}_2{\mathrm{O}}_4\right)=100 \mathrm{kJ}$ and $\Delta G_f^0\left({\mathrm{NO}}_2\right)=50 \mathrm{kJ}$, find $\Delta G$ of the reaction

In the following equilibrium  ${\mathrm{N}}_2{\mathrm{O}}_4\left(\mathrm{g}\right)\rightleftharpoons 2{\mathrm{NO}}_2\left(\mathrm{g}\right)$

When $5$ mole of each are taken, the temperature is kept at $298 \mathrm{K}$. The total pressure was found to be $20$ bar. Given: $\Delta G_f^0\left({ \mathrm{N}}_2{\mathrm{O}}_4\right)=100 \mathrm{kJ}$ and $\Delta G_f^0\left({\mathrm{NO}}_2\right)=50 \mathrm{kJ}$, the direction of the reaction in which the equilibrium shifts.

If $0.1\mathrm{MHA}$ is titrated with $0.1\mathrm{MNaOH}$, calculate the $\mathrm{pH}$ at the end point. ${\mathrm{K}}_{\mathrm{a}}\left(\mathrm{HA}\right)=5\times {10}^{-6}$ and $\alpha \ll 1$.

(a) Calculate the velocity of electrons in the first Bohr orbit of hydrogen atom. 

$\mathrm{r}={\mathrm{a}}_0=0.53\times {10}^{-10} \mathrm{m}.$

(b) Find the de Broglie wavelength of the electron in the first orbit.

(c) Find the orbital angular momentum of the $2\mathrm{p}$ orbital in terms of $\mathrm{h}/2\mathrm{\pi }$ units.

For the reaction

Given:

calculate  $at298K.$

$\Delta {\mathrm{G}}_{\mathrm{reac}}^{\mathrm{o}}$  represent the reaction as cell calculate ${\mathrm{E}}_{\mathrm{cell}}^{\mathrm{o}}$ & find ${\log }_{10} \mathrm{Ksp}$ for $\mathrm{AgCl}$.

$6.539\times {10}^{-2} \mathrm{g}$ of metallic $\mathrm{Zn}$ was added to $100 \mathrm{mL}$ of saturated solution of $\mathrm{AgCl}$. Calculate $\log \left(\left[{\mathrm{Zn}}^{2+}\right]/{\left[{\mathrm{Ag}}^{+}\right]}^2\right)$.

Given: ${\mathrm{Ag}}^{+}+\mathrm{e}=\mathrm{Ag};{\mathrm{E}}^0=0.80 \mathrm{V}$

${\mathrm{Zn}}^{2+}+2\mathrm{e}=\mathrm{Zn}; {\mathrm{E}}^0=-0.76 \mathrm{V}$

Also find how many moles of Ag will be formed.