The pair(s) of complexes wherein both exhibit tetrahedral geometry is(are)

(Note : py = pyridine)

Given : Atomic numbers of Fe, Co, Ni and Cu are 26, 27, 28 and 29, respectively)

The correct statement(s) related to oxoacids of phosphorous is(are)

At 298 K, the limiting molar conductivity of a weak monobasic acid is 4 $$\times$$ 10² S cm² mol^$$-$$1. At 298 K, for an aqueous solution of the acid the degree of dissociation is $$\alpha$$ and the molar conductivity is y $$\times$$ 10² S cm² mol^$$-$$1. At 298 K, upon 20 times dilution with water, the molar conductivity of the solution becomes 3y $$\times$$ 10² S cm² mol^$$-$$1.

The value of $$\alpha$$ is __________.

At 298 K, the limiting molar conductivity of a weak monobasic acid is 4 $$\times$$ 10² S cm² mol^$$-$$1. At 298 K, for an aqueous solution of the acid the degree of dissociation is $$\alpha$$ and the molar conductivity is y $$\times$$ 10² S cm² mol^$$-$$1. At 298 K, upon 20 times dilution with water, the molar conductivity of the solution becomes 3y $$\times$$ 10² S cm² mol^$$-$$1.

The value of y is __________.