Which from following species acts as base ${ }^1$, according to Bronsted-Lowry theory?

$$\mathrm{HCl}+\mathrm{NH}_3 \text { 目的 } \mathrm{NH}_4^{+}+\mathrm{Cl}^{-} $$

Which of the following reactions represents Clemmensen reduction?

Which from following catalysts is used in the Haber's process for manufacture of ammonia?

In a first order reaction if concentartion of reactant drops from $0.8 \mathrm{~mol} \mathrm{~L}^{-1}$ to $0.4 \mathrm{~mol} \mathrm{~L}^{-1}$ in 15 minute. What is the time required to drop concentration from $0.1 \mathrm{~mol} \mathrm{~L}^{-1}$ to 0.025 mol $\mathrm{L}^{-1}$.