A metal M forms a volatile carbonyl complex $M(CO)_x$. 0.525g of this complex is heated in a closed vessel of volume 250 mL at $50^\circ C$. The pressure inside the vessel after complete decomposition of the complex is 746 Torr. If the gas constant R is 0.0821 L atm $K^{-1} mol^{-1}$, what is the value of x in the formula $M(CO)_x$? (Assume the metal M does not contribute significantly to the pressure)

In the following change, $3{\rm{Fe}} + 4{{\rm{H}}_2}{\rm{O}} o {\rm{F}}{{\rm{e}}_3}{{\rm{O}}_4} + 4{{\rm{H}}_2}$. If the atomic weight of iron is 56, then its equivalent weight will be :

In the reaction, ${\rm{VO}} + {\rm{F}}{{\rm{e}}_2}{{\rm{O}}_3} o {\rm{FeO}} + {{\rm{V}}_2}{{\rm{O}}_5}{\rm{.}}$. The eq.wt. of ${{\rm{V}}_2}{{\rm{O}}_5}$ is equal to its :

In the standardization of ${\rm{N}}{{\rm{a}}_2}{{\rm{S}}_2}{{\rm{O}}_3}$ using ${{\rm{K}}_2}{\rm{C}}{{\rm{r}}_2}{{\rm{O}}_7}$ by iodometry, the equivalent weight of ${{\rm{K}}_2}{\rm{C}}{{\rm{r}}_2}{{\rm{O}}_7}$ is :