Ethyl phenyl acetylene ($1$-phenyl-but-$1$-yne) on reduction with partially deactivated palladised charcoal (Lindlar's catalyst) gives:

One mole of a symmetrical alkene on ozonolysis gives two moles of an aldehyde having a molecular mass of $44 \ u$. The alkene is

$A$ dibromide $X$ $(C_4H_8Br_2)$ on dehydrohalogenation gave $Y$,which on reduction with $Z$ gave a non-polar isomer of $C_4H_8$. What are $X$ and $Z$ respectively?

What is the product formed when $1$-butene is heated with $Al_2(SO_4)_3$ at $500 \ K$?

$A$ hydrocarbon '$X$' with formula $C_6H_8$ uses two moles of $H_2$ on catalytic hydrogenation of its one mole. On ozonolysis,'$X$' yields two moles of methane dicarbaldehyde (malonaldehyde). The hydrocarbon '$X$' is :

Among the following, the compound having conjugated double bonds is