An alkene $X$ on ozonolysis gives a mixture of propan-2-one and methanal. What is $X$ ?

The formula of a metal oxide is $M_{0.96} \mathrm{O}_1$. The fractions of metal that exists as $M^{3+}$ and $M^{2+}$ ions in that oxide are respectively

At $50^{\circ} \mathrm{C}$, the vapour pressure of pure benzene is 268 torr. The number of moles of non-volatile solute per mole of benzene required to prepare a solution having a vapour pressure of 167 torr at the same temperature is (molar mass of benzene $=78 \mathrm{~g} \mathrm{~mol}^{-1}$ )

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