Writtenভর্তি পরীক্ষা - Rajshahi University of Engineering & Technology (17-18)
(a) কিভাবে পাওয়া যায়, সমীকরণসহ লিখ ।
(i) মিথেন থেকে ক্লোরোফর্ম।
(ii) ফেনল থেকে অ্যানিলিন ।
(b) কোনটি কি?
(i) এস্টার
(ii) পি.ভি.সি
(iii) ডিটারজেন্ট
উত্তর ও বিস্তারিত ব্যাখ্যা
সঠিক উত্তর: ক
(a) (i) Preparation of chloroform from methane:
Methane reacts with chlorine in the presence of sunlight or at high temperature (400°C) to undergo successive substitution reactions, eventually forming chloroform.
$$
\begin{aligned}
\mathrm{CH}_4 + \mathrm{Cl}_2 &\xrightarrow{400^{\circ}\mathrm{C}} \mathrm{CH}_3\mathrm{Cl} + \mathrm{HCl} \\
\mathrm{CH}_3\mathrm{Cl} + \mathrm{Cl}_2 &\xrightarrow{400^{\circ}\mathrm{C}} \mathrm{CH}_2\mathrm{Cl}_2 + \mathrm{HCl} \\
\mathrm{CH}_2\mathrm{Cl}_2 + \mathrm{Cl}_2 &\xrightarrow{400^{\circ}\mathrm{C}} \mathrm{CHCl}_3 + \mathrm{HCl}
\end{aligned}
$$
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(ii) Preparation of aniline from phenol:
Phenol is first converted to benzene by reduction with zinc dust, then nitrated to nitrobenzene, and finally reduced to aniline.
$$
\begin{aligned}
\mathrm{C}_6\mathrm{H}_5\mathrm{OH} + \mathrm{Zn} &\rightarrow \mathrm{C}_6\mathrm{H}_6 + \mathrm{ZnO} \\
\mathrm{C}_6\mathrm{H}_6 + \mathrm{HNO}_3 &\xrightarrow{\mathrm{H}_2\mathrm{SO}_4} \mathrm{C}_6\mathrm{H}_5\mathrm{NO}_2 + \mathrm{H}_2\mathrm{O} \\
\mathrm{C}_6\mathrm{H}_5\mathrm{NO}_2 + 6[\mathrm{H}] &\xrightarrow{\mathrm{Sn/HCl}} \mathrm{C}_6\mathrm{H}_5\mathrm{NH}_2 + 2\mathrm{H}_2\mathrm{O}
\end{aligned}
$$
(b) Identification of the compounds:
(i) Ester: These are organic compounds characterized by the functional group $\mathrm{R}-\mathrm{COO}-\mathrm{R}'$.
(ii) PVC (Polyvinyl chloride): This is a polymer formed by the polymerization of vinyl chloride monomer, represented as $\left(-\mathrm{CH}_2-\mathrm{CHCl}-\right)_n$.
(iii) Detergent: These are synthetic surfactants, commonly sodium alkyl benzene sulfonates or alkyl sulfates, represented by the general formula $\mathrm{R}-\mathrm{O}-\mathrm{SO}_3\mathrm{Na}$.
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