If the de Broglie wavelength of the electron in n^th Bohr orbit in a hydrogenic atom is equal to 1.5 $$\pi $$a₀ (a₀ is Bohr radius), then the value of n/z is -

Given

(i)  C (graphite) + O₂(g) $$ \to $$ CO₂(g); $$\Delta $$rH$$^\Theta $$ = x kJ mol^$$-$$1

(ii)  C(graphite) + $${1 \over 2}$$O₂(g) $$ \to $$ CO(g); $$\Delta $$rH$$^\Theta $$ = y kJ mol^$$-$$1

(iii)  CO(g) + $${1 \over 2}$$ O₂(g) $$ \to $$ CO₂(g); $$\Delta $$rH$$^\Theta $$ = z kJ mol^$$-$$1

Based on the above thermochemical equations, find out which one of the following algebraic relationships is correct?

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

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 -