Two buffers, $\left(\mathrm{X}\right)$ and $\left(\mathrm{Y}\right)$ of $\mathrm{pH} 4.0$ and $6.0$ respectively, are prepared from acid $\mathrm{HA}$ and the salt $\mathrm{NaA}$. Both the buffers are $0.50 \mathrm{M}$ in $\mathrm{HA}$. What would be the $\mathrm{pH}$ of the solution obtained by mixing equal volumes of the two buffers?

Round off your answer to the nearest integer.

${\mathrm{K}}_{\mathrm{a}}\left(\mathrm{HA}\right)=1.0\times {10}^{-5}$

Calculate the value of $\log {\mathrm{K}}_{\mathrm{p}}$ for the reaction: ${\mathrm{N}}_2\left(\mathrm{g}\right)+3{\mathrm{H}}_2\left(\mathrm{g}\right)\rightleftharpoons 2{\mathrm{NH}}_3\left(\mathrm{g}\right)$ at $25°\mathrm{C}$. The standard enthalpy of formation of ${\mathrm{NH}}_3\left(\mathrm{g}\right)$ is $-46 \mathrm{kJ}$ and the standard entropies of ${\mathrm{N}}_2, {\mathrm{H}}_2$ and ${\mathrm{NH}}_3$ gases are $191, 130, 192 {\mathrm{JK}}^{-1} {\mathrm{mol}}^{-1}$, respectively. 

Round off your answer to the nearest integer.

Determine the concentration of ${\mathrm{NH}}_3$ solution, one litre of which can dissolve $0.10 \mathrm{mole}$ $\mathrm{AgCl}. {\mathrm{K}}_{\mathrm{sp}}$ of $\mathrm{AgCl}$ and ${\mathrm{K}}_{\mathrm{f}}$ of $\mathrm{Ag}{\left({\mathrm{NH}}_3\right)}_2^{+}$ are $1.0\times {10}^{-10} {\mathrm{M}}^2$ and $1.6\times {10}^7 {\mathrm{M}}^{-2}$ respectively.

At $817 °\mathrm{C}, {\mathrm{K}}_{\mathrm{p}}$ for the reaction between ${\mathrm{CO}}_2\left(\mathrm{g}\right)$ and excess hot graphite(s) is $10 \mathrm{atm}$. What are equilibrium concentrations of the gases at $817 °\mathrm{C}$ and a total pressure of $5 \mathrm{atm}.$

$\mathrm{At} 817 °\mathrm{C}, {\mathrm{K}}_{\mathrm{p}}$ for the reaction between ${\mathrm{CO}}_2\left(\mathrm{g}\right)$ and excess hot graphite(s) is $10 \mathrm{atm}$. At what total pressure (in atm), the gas contains $5\% {\mathrm{CO}}_2$ by volume?

Answer correct up to three places of decimal.

The rate law of the reaction is given as $2 \mathrm{A}+\mathrm{B}\to$product.

Rate$=\mathrm{k}{\left[\mathrm{A}\right]}^2\left[\mathrm{B}\right]$

Find $\mathrm{x}$.