In Tollen's test for aldehyde, the overall number of electron(s) transferred to the Tollen's reagent formula [Ag(NH₃)₂]⁺ per aldehyde group to form silver mirror is ___________. (Round off to the Nearest Integer).

10.0 mL of Na₂CO₃ solution is titrated against 0.2 M HCl solution. The following titre values were obtained in 5 readings :

4.8 mL, 4.9 mL, 5.0 mL, 5.0 mL and 5.0 mL

Based on these readings, and convention of titrimetric estimation the concentration of Na₂CO₃ solution is ___________ mM.

(Round off to the Nearest Integer).

A xenon compound 'A' upon partial hydrolysis gives XeO₂F₂. The number of lone pair of electrons present in compound A is _________. (Round off to the Nearest Integer)

The number of species below that have two lone pairs of electrons in their central atom is _________. (Round off to the Nearest Integer).

SF₄, BF$$_4^ - $$, ClF₃, AsF₃, PCl₅, BrF₅, XeF₄, SF₆