The catalyst used for the isomerisation of $n$-alkanes to branched chain alkanes is

An element crystallises in bcc lattice. The atomic radius of the element is $2.598 \mathop {\rm{A}}\limits^{\rm{o}}$. What is the volume (in $\mathrm{cm}^3$ ) of one unit cell?

A centi molar solution of acetic acid is $50 \%$ dissociated at $27^{\circ} \mathrm{C}$. The osmotic pressure of the solution (in atm ) is $\left(R=0.083 \mathrm{~L}\right.$ atm $\left.\mathrm{K}^{-1} \mathrm{~mol}^{-1}\right)$

At 300 K vapour pressure of a pure liquid. ' $A$ ' is 70 mm Hg . It forms an ideal solution with another liquid ' $B$ '. The mole fraction of $B$ in the solution is 0.2 and total vapour pressure of solution is 84 mm Hg at same temperature. What is the vapour pressure (in mm ) of pure liquid $B$ at 300 K ?