What is percent dissociation of $\mathrm{NH}_4 \mathrm{OH}$ if molar conductance at zero concentration for $\mathrm{NH}_4 \mathrm{Cl}$, NaCl and NaOH are 130, 109 and $213 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1}$ respectively and molar conductivity of $0.01 \quad \mathrm{M} \quad \mathrm{NH}_4 \mathrm{OH}$ is $9.0 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1}$ ?

Identify the reagent used for Rosenmund reduction.

Calculate the work done in the oxidation of one mole $\mathrm{HCl}_{(\mathrm{g})}$ at $27^{\circ} \mathrm{C}$, according to reaction.

$$ \begin{aligned} & 4 \mathrm{HCl}_{(\mathrm{g})}+\mathrm{O}_{2(\mathrm{~g})} \longrightarrow 2 \mathrm{Cl}_{2(\mathrm{~g})}+2 \mathrm{H}_2 \mathrm{O}_{(\mathrm{g})} \\ & \left(\mathrm{R}=8.314 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\right) \end{aligned} $$

Find the concentration of sodium acetate when added to 0.1 M solution of acetic acid to form a buffer solution of $\mathrm{pH}=5.5$ ?

( $\mathrm{pK}_{\mathrm{a}}$ of $\mathrm{CH}_3 \mathrm{COOH}=4.5$ )