Match the thermodynamics processes given under column I with expression given under column II

Column I
(A) Freezing water at 273 K and 1 atm
(B) Expansion of 1 mol of an ideal gas into a vacuum under isolated conditions.
(C) Mixing of equal volumes of two ideal gases at constant temperature and pressure in an isolated container.
(D) Reversible heating of H₂(g) at 1 atm from 300K to 600K, followed by reversible cooling to 300K at 1 atm

Column II
(p) q = 0
(q) w = 0
(r) $$\Delta S_{sys}$$ < 0
(s) $$\Delta U$$ = 0
(t) $$\Delta G$$ = 0

Among the triatomic molecules/ions, BeCl₂, $$N_3^-$$, N₂O, $$NO_2^+$$, O₃, SCl₂, $$ICl_2^-$$, $$I_3^-$$ and XeF₂, the total number of linear molecule(s)/ion(s) where the hybridization of the central atom does not have contribution from the d-orbital(s) is

[Atomic number: S = 16, Cl = 17, I = 53 and Xe = 54]

Not considering the electronic spin, the degeneracy of the second excited state( n = 3) of H atom is 9, while the degeneracy of the second excited state of H^– is ___________.

The total number of stereoisomers that can exist for M is ___________.