In a solid AB, A atoms are in ccp arrangement and B atoms occupy all the octahedral sites. If two atoms from the opposite faces are removed, then the resultant stoichiometry of the compound is A_xB_y. The value of x is ____________. [nearest integer]

The distance between Na⁺ and Cl^$$-$$ ions in solid NaCl of density 43.1 g cm^$$-$$3 is _______________ $$\times$$ 10^$$-$$10 m. (Nearest Integer)

(Given : N_A = 6.02 $$\times$$ 10²³ mol^$$-$$1)

Atoms of element X form hcp lattice and those of element Y occupy $${2 \over 3}$$ of its tetrahedral voids. The percentage of element X in the lattice is ____________. (Nearest integer)