120 g of an organic compound that contains only carbon and hydrogen gives 330 g of CO₂ and 270 g of water on complete combustion. The percentage of carbon and hydrogen, respectively are

The energy of one mole of photons of radiation of wavelength 300 nm is

(Given : h = 6.63 $$\times$$ 10^$$-$$34 J s, N_A = 6.02 $$\times$$ 10²³ mol^$$-$$1, c = 3 $$\times$$ 10⁸ m s^$$-$$1)

The correct order of bond orders of $${C_2}^{2 - }$$, $${N_2}^{2 - }$$ and $${O_2}^{2 - }$$

At 25$$^\circ$$C and 1 atm pressure, the enthalpies of combustion are as given below :

The enthalpy of formation of ethane is