Consider the following redox reaction taking place in acidic medium

$$ \mathrm{BH}_4^{-}(a q)+\mathrm{ClO}_3^{-}(a q) \longrightarrow \mathrm{H}_2 \mathrm{BO}_3^{-}(a q)+\mathrm{Cl}^{-}(a q) $$

If the Nernst equation for the above balanced reaction is

$$ \mathrm{E}_{\mathrm{cell}}=\mathrm{E}_{\mathrm{cell}}^{\circ}-\frac{\mathrm{RT}}{\mathrm{nF}} \ln \mathrm{Q}, $$

then the value of $n$ is $\_\_\_\_$ .(Nearest integer)

X is the number of geometrical isomers exhibited by $\left[\mathrm{Pt}\left(\mathrm{NH}_3\right)\left(\mathrm{H}_2 \mathrm{O}\right) \mathrm{BrCl}\right]$.

Y is the number of optically inactive isomer(s) exhibited by $\left[\mathrm{CrCl}_2(\mathrm{ox})_2\right]^{3-}$

Z is the number of geometrical isomers exhibited by $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_3\left(\mathrm{NO}_2\right)_3\right]$.

The value of $\mathrm{X}+\mathrm{Y}+\mathrm{Z}$ is $\_\_\_\_$ .

Consider the dissociation equilibrium of the following weak acid

$$ \mathrm{HA} \rightleftharpoons \mathrm{H}^{+}(\mathrm{aq})+\mathrm{A}^{-}(\mathrm{aq}) $$

If the pKa of the acid is 4 , then the pH of 10 mM HA solution is $\_\_\_\_$ .(Nearest integer)

[Given: The degree of dissociation can be neglected with respect to unity]

0.53 g of an organic compound $(\mathrm{x})$ when heated with excess of nitric acid (concentrated) and then with silver nitrate gave 0.75 g of silver bromide precipitate. 1.0 g of $(\mathrm{x})$ gave 1.32 g of $\mathrm{CO}_2$ gas on combustion. The percentage of hydrogen in the compound $(x)$ is $\_\_\_\_$ %. [Nearest Integer]

[Given: Molar mass in $\mathrm{g} \mathrm{mol}^{-1} \mathrm{H}: 1, \mathrm{C}: 12, \mathrm{Br}: 80, \mathrm{Ag}: 108, \mathrm{O}: 16$; Compound (x) : $\left.\mathrm{C}_{\mathrm{x}} \mathrm{H}_{\mathrm{y}} \mathrm{Br}_{\mathrm{z}}\right]$