Chlorination can be done on

In the following reactions,the product $S$ is

What is the correct order of acidity for the following hydrocarbons?

Match the following reactions with their nature and choose the correct code.

Reaction	Nature of reaction
$A. RBr \xrightarrow{Na}$	$1. \text{Partial reduction}$
$B. RCOO^-Na^+ \xrightarrow{NaOH/CaO, \Delta}$	$2. \text{Electrophilic addition}$
$C. R-C \equiv C-R' \xrightarrow{\text{Lindlar's catalyst } (H_2)}$	$3. \text{Wurtz reaction}$
$D. H_2C=CH_2 \xrightarrow{Br_2/CCl_4}$	$4. \text{Decarboxylation}$
	$5. \text{Decarboxylative dimerisation}$

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)

The major product of the following reaction contains $.....$ bromine atom$(s)$.