In which of the following ionization processes the bond energy increases and the magnetic behaviour changes from paramagnetic to diamagnetic.

When 5 litres of a gas mixture of methane and propane is perfectly combusted at 0^oC and 1 atmosphere, 16 litres of oxygen at the same temperature and pressure is consumed, The amount of heat released from this combustion in kJ ($$\Delta $$H_comb. (CH₄) = 890 kJ mol^$$-$$1, $$\Delta $$H_comb. (C₃H₈) = 2220 kJ mol^$$-$$1) is

Accumulation of lactic acid (HC₃H₅O₃), a monobasic acid in tissues leads to pain and a feeling of fatigue. In a 0.10 M aqueous solution, lactic acid is 3.7% dissociates. The value of dissociation constant, K_a, for this acid will be

The dissociation constant of weak acid is 1 $$ \times $$ 10^$$-$$4. In order to prepare a buffer solution with a pH = 5, the [Salt]/[Acid] ratio should be