If the following compound is treated with $Pd/C$ in excess of hydrogen gas,how many stereoisomers of the product will be obtained?

$CH_2(COOH)_2 \xrightarrow{P_4O_{10}, \, 150^\circ C} X$
Compound $(X)$ is

Which of the following compounds shall not produce propene by reaction with $HBr$ followed by elimination or direct only elimination reaction?

Classify the following compounds into saturated,unsaturated,and aromatic hydrocarbons: Ethane,Ethene,Ethyne,Propene,Propane,Benzene,Toluene,Anthracene,Cyclopropane.

Relationship between products $(Q)$ and $(S)$ is
$CH_3-CH=CH_2$ $\xrightarrow[H_2O_2, OH^{-}]{BH_3, THF}$ $(P)$ $\xrightarrow[CH_2Cl_2]{PCC}$ $(Q)$
$CH_3-CH=CH_2$ $\xrightarrow[NaBH_4, HO^{-}]{Hg(OAc)_2, H_2O}$ $(R)$ $\xrightarrow[CH_2Cl_2]{PCC}$ $(S)$

Give distinguishing tests for the following:
$(a)$ Ethane and ethyne (Alkane and Alkyne $RC \equiv CH$)
$(b)$ Ethene and Ethyne (Alkene and Alkyne $RC \equiv CH$)
$(c)$ Dimethyl ethyne and ethyne
$(d)$ Ethane and Ethene (Alkane and alkene)