What is the total number of $\pi$ bonds in the compound $CH_2=CH-CH=CH-COOH$?

If the internuclear axis is $z$,then which of the following overlapping gives a $\sigma$ bond?

$A$ molecule $(X)$ has $(i)$ four sigma bonds formed by the overlap of $sp^2$ and $s$ orbitals,(ii) one sigma bond formed by $sp^2$ and $sp^2$ orbitals,and (iii) one $\pi$ bond formed by $p_z$ and $p_z$ orbitals. Which of the following is $X$?

In a double bond between two carbon atoms of ethene,there are

Which of the following is correct for the $N_2$ triple bond?

The strongest bond is formed when atomic orbitals undergo: