The $\mathrm{H}-\mathrm{P}-\mathrm{H}$ angle in ${\mathrm{PH}}_3$ is smaller than that of $\mathrm{H}-\mathrm{N}-\mathrm{H}$ angle in ${\mathrm{NH}}_3$. Explain?

Which one of each of the following pairs is expected to have the larger bond angle?

${\mathrm{H}}_2\mathrm{O}$ and ${\mathrm{NH}}_3$

Which one of each of the following pairs is expected to have the larger bond angle?

${\mathrm{SH}}_2$ and ${\mathrm{BeF}}_2$

Which one of each of the following pairs is expected to have the larger bond angle?

 ${\mathrm{BF}}_3$ and ${\mathrm{BF}}_4^{-}$ 

Which one of each of the following pairs is expected to have the larger bond angle?

${\mathrm{NH}}_3$ and ${\mathrm{PH}}_3$

Which one of each of the following pairs is expected to have the larger bond angle?

${\mathrm{NH}}_3$ and ${\mathrm{NF}}_3$

Which is correct statement?

As the $\%\mathrm{s}$-character of a hybrid orbital decreases ______.

(I) The bond angle decreases
(II) The bond strength increases
(III) The bond length increases
(IV) The size of orbital increases

The table shown below gives the bond dissociation energies ${\left(\mathrm{E}\right)}_{\mathrm{diss}}$ for single covalent bonds of carbon atoms with element $\text{'}\mathrm{A}\text{'}, \text{'}\mathrm{B}\text{'}, \text{'}\mathrm{C}\text{'}$ and $\text{'}\mathrm{D}\text{'}$. Which element has the smallest atoms?

$\begin{array}{|lc|}\hline \text{ Bond }& {\mathrm{E}}_{\text{diss }}\left({\mathrm{kJmol}}^{-1}\right)\\ \mathrm{C}-\mathrm{A}& 240\\ \mathrm{C}-\mathrm{B}& 328\\ \mathrm{C}-\mathrm{C}& 276\\ \mathrm{C}-\mathrm{D}& 485\\ \hline\end{array}$