The rate law for the decomposition of hydrogen iodide is $-\frac{d[\mathrm{HI}]}{d t}=k[\mathrm{HI}]^2$. The units of rate constant $k$ are

A current of 15.0 A is passed through a solution of $\mathrm{CrCl}_2$ for 45 minutes. The volume of $\mathrm{Cl}_2$ (in L ) obtained at the anode at 1 atm and 273 K is around (IF $=96500 \mathrm{C} \mathrm{mol}^{-1}$, atomic wt. of $\mathrm{Cl}=35.5, R=0.082 \mathrm{L}-\mathrm{atm} \mathrm{K}^{-1} \mathrm{~mol}^{-1}$ )

Which of the following can form ionic micelles in water?

The ore which is purified by leaching process is