In which of the following reactions is hydrogen gas not liberated?

Assertion : Both $Be$ and $Al$ can form complexes such as $BeF_4^{2-}$ and $AlF_6^{3-}$ respectively,$BeF_6^{3-}$ is not formed.
Reason : In case of $Be$,no vacant $d-$orbitals are present in its outermost shell.

If $(2,-1,3)$ is the foot of the perpendicular drawn from the origin to the plane,then the equation of the plane is

$A$ wire in the form of a square of side '$a$' carries a current $i$. Then the magnetic induction at the centre of the square wire is (Magnetic permeability of free space = $\mu_0$)

$A$ particle moves in a circle of radius $25 \, cm$ at two revolutions per second. The acceleration of the particle in $m/s^2$ is

Which of the following is not included in the five-kingdom classification system?