To resist the coagulation of 100 cc gold sol; 1 cc of $10 \% \mathrm{NaCl}$ is added to it in the presence of $10^{-4} \mathrm{~g}$ gelatin. The gold number of gelatin is

In the following reactions, identify $P, Q$ and $R$, respectively

I. $3 \mathrm{Fe}_2 \mathrm{O}_3+\mathrm{CO} \longrightarrow 2 P+\mathrm{CO}_2 \uparrow$

II. $\mathrm{Fe}_3 \mathrm{O}_4+4 \mathrm{CO} \longrightarrow 3 Q+4 \mathrm{CO}_2 \uparrow$

III. $\mathrm{Fe}_2 \mathrm{O}_3+\mathrm{CO} \longrightarrow 2 R+\mathrm{CO}_2 \uparrow$

The number of dissociable protons in "orthophosphoric acid" is

The geometry of $\mathrm{XeOF}_4$ is