When the excited electron of a H atom from n = 5 drops to the ground state, the maximum number of emission lines observed are _____________.

While performing a thermodynamics experiment, a student made the following observations.

HCl + NaOH $$\to$$ NaCl + H₂O $$\Delta$$H = $$-$$57.3 kJ mol^$$-$$1

CH₃COOH + NaOH $$\to$$ CH₃COONa + H₂O $$\Delta$$H = $$-$$55.3 kJ mol^$$-$$1

The enthalpy of ionization of CH₃COOH as calculated by the student is _____________ kJ mol^$$-$$1. (nearest integer)

For the decomposition of azomethane.

CH₃N₂CH₃(g) $$\to$$ CH₃CH₃(g) + N₂(g), a first order reaction, the variation in partial pressure with time at 600 K is given as

The half life of the reaction is __________ $$\times$$ 10^$$-$$5 s. [Nearest integer]

The sum of number of lone pairs of electrons present on the central atoms of XeO₃, XeOF₄ and XeF₆, is ______________