What is the bond angle observed in the $H-C-H$ bond of ethane (in $^{\circ}$)?

The mean values for the radial distance for different phosphorus orbitals are $3s: 0.47 \ \mathring{A}$,$3p: 0.55 \ \mathring{A}$,$3d: 2.4 \ \mathring{A}$. When $P$ is going to form $PF_5$,then these radial distances are going to become arbitrarily . . . . . . , . . . . . . and . . . . . . respectively.

Identify the compound which is polar and has the central atom in $sp^2$ hybridization.

The number of $sp^2 - sp^2$ sigma bonds in the compound given below is

As the $s-$character of a hybridized orbital decreases,the bond angle

Which of the following molecules is tetrahedral?