Integrated rate law equation for a first order gas phase reaction is given by (where $\mathrm{P}_{\mathrm{i}}$ is initial pressure and $\mathrm{P}_{\mathrm{t}}$ is total pressure at time $t$)

1. A $k=\frac{2.303}{t} \times \log \frac{P_i}{\left(2 P_i-P_t\right)}$ Correct answer
2. B $$\mathrm{k}=\frac{2.303}{\mathrm{t}} \times \log \frac{\left(2 \mathrm{P}_{\mathrm{i}}-\mathrm{P}_{\mathrm{t}}\right)}{\mathrm{P}_{\mathrm{i}}}$$
3. C $k=\frac{2.303}{t} \times \frac{P_i}{\left(2 P_i-P_t\right)}$
4. D $$\mathrm{k}=\frac{2.303}{\mathrm{t}} \times \log \frac{2 \mathrm{P}_{\mathrm{i}}}{\left(2 \mathrm{P}_{\mathrm{i}}-\mathrm{P}_{\mathrm{t}}\right)}$$