$ t_{1/2}= \frac{{{{[R]}_0}}}{{2K}}$
$\therefore \,K = $ $\frac{{{{[R]}_0}}}{{2 t_{1/2}}}$$ = \frac{2}{{2 \times 1}} = 1$ મોલર કલાક $^{-1}$
$\therefore \,\,{\text{t}} = \frac{{{{{\text{[R]}}}_{\text{0}}} - {{[R]}_t}}}{K}\,\,\,$
$\,\therefore \,\,\,t = \frac{{0.5 - 0.25}}{1} = 0.25$ કલાક