For a reaction consider the plot of $$\ell $$n k versus 1/T given in the figure. If the rate constant of this reaction at 400 K is 10^–5 s^–1, then the rate constant at 500 K is –

The increasing order of the reactivity of the following with LiAlH₄ is

8 g of NaOH is dissolved in 18g of H₂O. Mole fraction of NaOH in solution and molality (in mol kg^–1) of the solution respectively are -

The upper stratosphere consisting of the ozone layer protects us from sun's radiation that falls in the wavelength region of -