Chemistry - Chemical Equilibrium Question with Solution | TestHub

(i) The haemoglobin of RBC combines with oxygen in lungs following the equilibrium,
${\mathrm{H}}_{\mathrm{b}}\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\rightleftharpoons {\mathrm{H}}_{\mathrm{b}}{\mathrm{O}}_2\left(\mathrm{s}\right)$
When these are at lungs, the partial pressure of${\mathrm{O}}_2$being appreciable show forward reaction, however when they pass to tissues, the partial pressure of${\mathrm{O}}_2$decreases to favour backward reaction releasing${\mathrm{O}}_2$.
(ii) Removal of$\mathrm{C}{\mathrm{O}}_2$from blood is based on the equilibrium,
$\mathrm{C}{\mathrm{O}}_2\left(\mathrm{g}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\rightleftharpoons {\mathrm{H}}^{+}\left(\mathrm{a}\mathrm{q}\right)+\mathrm{H}\mathrm{C}{\mathrm{O}}_3^{-}\left(\mathrm{a}\mathrm{q}\right)$
In tissues$\mathrm{C}{\mathrm{O}}_2$gets dissolved in${\mathrm{H}}_2\mathrm{O}$due to high pressure whereas in lungs, the$\mathrm{C}{\mathrm{O}}_2$is released out because of low pressure of$\mathrm{C}{\mathrm{O}}_2$.
(iii) Tooth enamel substance (Hydroxyapatite)$\mathrm{C}{\mathrm{a}}_5(\mathrm{P}{\mathrm{O}}_4{)}_3\mathrm{O}\mathrm{H}$shows the following equilibrium,
${\text{Ca}}_{\text{5}}{{\text{(PO}}_{\text{4}}\text{)}}_{\text{3}}\text{OH}\stackrel{\text{Demineralization}}{\rightleftharpoons }{\text{5Ca}}^{\text{2+}}(\text{aq})\text{+}{\text{3PO}}_{\text{4}}^{\text{3}-}(\text{aq})\text{+}{\text{OH}}^{-}(\text{aq})$
The use of sweet material or fermentation produces${\mathrm{H}}^{+}$. Which combines with$\stackrel{-}{\mathrm{O}}\mathrm{H}$to favour demineralisation of enamel causing tooth decay.