Which of the following molecules is an example of $sp$ hybridization?

In $NO_2$ molecule,the $N$ atom undergoes which type of hybridization?

Which of the following compounds shows the hybridization mode $sp^2 - sp^2 - sp - sp$ from left to right?

The molecule of $CO_2$ has a $180^{\circ}$ bond angle. It can be explained on the basis of:

Which of the following statements is true regarding the $PCl_5$ molecule?
$(i)$ The two axial $P-Cl$ bonds in $PCl_5$ are longer than the three equatorial bonds.
$(ii)$ The axial bonds in $PCl_5$ are stronger than equatorial bonds.
$(iii)$ The axial bonds in $PCl_5$ are more stable than equatorial bonds.
$(iv)$ All five bonds in $PCl_5$ molecule are equivalent.

What is the hybridisation state of the central atom and the shape of the conjugate base of the ammonium ion?