question_answer

Match the following lists:

	List 1		List 2
A	Alkanes	1.	Molasses
B	Ethers	2.	Hell-Volhard-Zelinsky  reaction
C	\[\alpha -\] halogenation	3.	Williamson synthesis
D	Ethyl alcohol	4.	Wurtz reaction
		5.	Aldol condensation

The correct answer is:

A) A-4         B-3         C-2         D-1

B) A-3         B-4         C-2         D-5

C) A-2         B-5         C-3         D-4

D) A-5         B-2         C-3         D-4

Correct Answer: A

Solution :

Wurtz reaction: Alkyl halide when heated with metallic sodium and zinc powder in ether gives alkane by joining two alkyl groups. \[2RX+2Na\xrightarrow{\text{ether}}R.R+2NaX\] Williamson synthesis: It is the laboratory preparation of ether. \[\underset{\text{Sod}\text{.alkoxide}}{\mathop{RONa}}\,+\underset{\text{Alkyl}}{\mathop{XR}}\,\xrightarrow{\Delta }\underset{\text{Ether}}{\mathop{ROR}}\,+NaX\] Hell-Volhard-Zelinsky reaction: \[\alpha -\] chloro or \[\alpha -\] bromo acids are usually prepared by first converting the acid into its chloride and bromide and then carrying out chlorination or bromination. Thus is called HV Z reaction. So, is for \[\alpha -\] halogenation. \[\underset{\text{Add}}{\mathop{RC{{H}_{2}}COOH}}\,\xrightarrow{\text{P + B}{{\text{r}}_{\text{2}}}}\underset{\text{Acid}\,\text{bromide}}{\mathop{RC{{H}_{2}}CO.Br}}\,\] Aldol condensation: When aldehydes and ketones having \[\alpha -\] hydogen atoms are treated with alkali they undergo self-addition between two molecules to form a \[\beta -\] hydroxy aldehyde or ketone (known as aldol). This addition is usually followed by elimination of a water molecule resulting in overall condensation reaction. \[C{{H}_{3}}CHO+C{{H}_{3}}CHO\xrightarrow{O{{H}^{-}}}\underset{\begin{smallmatrix}  \beta -\text{hydroxy}\,\text{butyraldehyde} \\  \text{(Aldol)} \end{smallmatrix}}{\mathop{C{{H}_{3}}-\underset{OH}{\mathop{\underset{|}{\mathop{CH}}\,}}\,-C{{H}_{2}}CHO}}\,\]Molasses: Ethyl alcohol is obtained from molasses. It is obtained as a byproduct of sugarindustry.