Which of the following is not considered as an organometallic compound?

$A$ particle is released from a height $H$. At a certain height,its kinetic energy is half of its potential energy with reference to the surface of the earth. The height and speed of the particle at that instant are respectively:

The molecular interactions responsible for hydrogen bonding in $HF$ are:

Let $R$ be a reflexive relation on a finite set $A$ having $n$ elements,and let there be $m$ ordered pairs in $R$. Then

How many integuments surround the ovule in $Pinus$ and $Cycas$?

If $PM$ is the perpendicular from $P(2, 3)$ onto the line $x+y=3$,then the coordinates of $M$ are