How many times solubility of $\mathrm{C}\mathrm{a}{\mathrm{F}}_2$ is decreased in $4\times {10}^{-3}\mathrm{M}\mathrm{}\mathrm{K}\mathrm{F}\left(\mathrm{a}\mathrm{q}\right)$ solution as compared to pure water at ${25}^{\mathrm{o}}\mathrm{C}?$ Given ${\mathrm{K}}_{\mathrm{s}\mathrm{p}}\left({\mathrm{C}\mathrm{a}\mathrm{F}}_2\right)=3.2\times {10}^{-11}?$

The remaining molar concentration of ${\mathrm{Ag}}^{+}$ ion if $100 \mathrm{mL}$ of $0.1\mathrm{M} {\mathrm{AgNO}}_3$ solution is mixed with $400 \mathrm{mL}$ of $0.2 \mathrm{M} {\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_4$ solution is,

[Given: ${\mathrm{K}}_{\mathrm{sp}}\left({\mathrm{Ag}}_2{\mathrm{CrO}}_4\right)=1.5\times {10}^{-11}{\mathrm{M}}^3$]

${\mathrm{N}}_2\left(\mathrm{g}\right)+3{\mathrm{H}}_2\left(\mathrm{g}\right)\rightleftharpoons 2{\mathrm{NH}}_3\left(\mathrm{g}\right)\text{ is }1.3\times {10}^{-Z}$

then calculate value of $\mathrm{z}$.