Question

Tritium, $T$ (an isotope of $H$) combines with fluorine to form weak acid $TF$, which ionizes to give $T^{+}$. Tritium is radioactive and is a $\beta -emitter$. A freshly prepared aqueous solution of $TF$ has $pT$ (equivalent of $pH$) of $1.5$ and freezes at $-{0.372}^{\circ }C$. If $600mL$ of freshly prepared solution were allotted to stand for $24.8years$.
If ionization constant of $TF$ is $K_a=7.3\times {10}^{-x}$, value of $x$ is:
(Given $K_f$ for water $=1.86kgmol{K}^{-1},t_{1/2}$ for tritium $=12.4years)$.

Answer 1

$P_T=1.5⟹\left[T^{+}\right]={10}^{-1.5}=0.0316=C_{\alpha }$

$0.372=\left(1.86\right)\left(C\right)(1+\alpha )$

$C+C_{\alpha }=0.2$

$C=0.1684$ $\alpha =0.1876$

$K_{\alpha }=\frac{C_{\alpha }2}{1-\alpha }=\frac{0.1684({0.1876)}^2}{1-0.1876}=7.3\times {10}^{-3}$

$⟶$ Value of $x=3.$