The synthesis of crotonaldehyde from acetaldehyde is an example of ........... reaction.

• nucleophilic addition

• elimination

• electrophilic addition

• nucleophilic addition-elimination

Which one of the following gives yellow precipitate with iodine and NaOH solution?

• CH₃—CHO

• C₆H₅COC₆H₅

• HCHO

• CH₃OH

Identify A, B and C in the following reactions

 ${\mathrm{CH}}_3\mathrm{Cl} + \stackrel{\mathrm{KCN}}{\to } \mathrm{A} \underset{{\mathrm{H}}_3{\mathrm{O}}^{\oplus }}{\overset{\mathrm{hydrolysis}}{\to }} \mathrm{B} \underset{∆}{\overset{{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}/ {\mathrm{H}}^{+}}{\to }} \mathrm{C}$

• $\underset{\mathrm{A}}{{\mathrm{CH}}_3\mathrm{NC}}, \underset{\mathrm{B}}{{\mathrm{CH}}_3{\mathrm{NHCH}}_3 ,} \underset{\mathrm{C}}{{\mathrm{CH}}_3-\mathrm{N}\left({\mathrm{CH}}_3\right)-{\mathrm{C}}_2{\mathrm{H}}_5}$

• $\underset{\mathrm{A}}{{\mathrm{CH}}_3\mathrm{CN}}, \underset{\mathrm{B}}{{\mathrm{CH}}_3{\mathrm{CONH}}_2},\underset{\mathrm{C}}{ {\mathrm{CH}}_3{\mathrm{CO}}_2\mathrm{H}}$

• $\underset{\mathrm{A}}{{\mathrm{CH}}_3\mathrm{CN}}, \underset{\mathrm{B}}{{\mathrm{CH}}_3{\mathrm{CO}}_2\mathrm{H}},\underset{\mathrm{C}}{ {\mathrm{CH}}_3{\mathrm{CO}}_2{\mathrm{C}}_2{\mathrm{H}}_5}$

• $\underset{\mathrm{A}}{{\mathrm{CH}}_3\mathrm{CN}}, \underset{\mathrm{B}}{{\mathrm{CH}}_3{\mathrm{CO}}_2\mathrm{H}}, \underset{\mathrm{C}}{({\mathrm{CH}}_3\mathrm{CO}{)}_2\mathrm{O}}$

684.

The reagent used in the Wolff-Kishner reduction is

• H₂N-NH₂/ KOH

• H₂/ Ni

• Sn/ HCl

• LiAlH₄

The pK_a values of four carboxylic acids are 4.76, 4.19, 0.23 and 3.41 respectively. The pK_a value ofstrongest carboxylic acid among them is

• 4.19

• 3.41

• 0.23

• 4.76

Compound A (C₃H₆O) undergoes following reactions to form B and C. Identify A, B and C.

   $\mathrm{C}\stackrel{\mathrm{Zn}-\mathrm{Hg}/\mathrm{HCl}}{\leftarrow } \underset{\mathrm{A}}{{\mathrm{C}}_3{\mathrm{H}}_6\mathrm{O} }\stackrel{{\mathrm{I}}_2/\mathrm{NaOH}}{\to } \mathrm{B}$

• $\underset{\mathrm{A}}{{\mathrm{H}}_3\mathrm{C}-\mathrm{CO}-{\mathrm{CH}}_3}, \underset{\mathrm{B}}{{\mathrm{CHI}}_3}, \underset{\mathrm{C}}{ {\mathrm{CH}}_3-{\mathrm{CH}}_2-{\mathrm{CH}}_3}$

• $\underset{\mathrm{A}}{{\mathrm{H}}_2\mathrm{C}=\mathrm{CH}-{\mathrm{CH}}_2\mathrm{OH}}, \underset{\mathrm{B}}{{\mathrm{CH}}_3\mathrm{I}},\underset{\mathrm{C}}{ {\mathrm{H}}_3\mathrm{C}-{\mathrm{CH}}_2-{\mathrm{CH}}_2-\mathrm{OH}}$

• $\underset{\mathrm{A}}{{\mathrm{H}}_3\mathrm{C}-{\mathrm{CH}}_2-\mathrm{CHO}}, \underset{\mathrm{B}}{{\mathrm{CHI}}_3}, \underset{\mathrm{C}}{{\mathrm{H}}_3\mathrm{C}-\mathrm{CHOH}-{\mathrm{CH}}_3}$

• $\underset{\mathrm{A}}{{\mathrm{H}}_3\mathrm{C}-\mathrm{CO}-{\mathrm{CH}}_3}, \underset{\mathrm{B}}{{\mathrm{CHI}}_3}, \underset{\mathrm{C}}{{\mathrm{H}}_3\mathrm{C}-{\mathrm{CHOHCH}}_3}$

Identify the product in the following reaction

Identify the reagents A and B respectively in the following reaction.

CH₃COOH $\stackrel{\mathrm{A}}{\to }$ CH₃COCl $\stackrel{\mathrm{B}}{\to }$ CH₃CHO

• SOCl₂, H₂/ Pd-BaSO₄

• H₂/ Pd-BaSO₄, SOCl₂

• SOCl₂, H₂O₂

• SOCl₂, O₅O₄

Predict respectively 'X and 'Y' in the following reactions.

Ar-NH₂ $\stackrel{\mathrm{X}}{\to }$ Ar-$\stackrel{+}{\mathrm{N}}$≡N

$\overline{\mathrm{Cl}} \stackrel{\mathrm{Y}}{\to } \mathrm{Ar}-\mathrm{Cl}$

• NaNO₃ and Cl₂

• NaNO₃ - HCl and HCl

• NaNO₂ - HCl and Cu/ HCl

• NaNO₂ - HCl and NaNH₂

What is Z in the following reaction sequence?

${\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{NH}}_2 \underset{\left(\mathrm{iii}\right) \mathrm{CO}, \mathrm{HCl} \mathrm{anhy} {\mathrm{AlCl}}_3/\mathrm{CuCl}}{\overset{\left(\mathrm{i}\right) {\mathrm{NaNO}}_2+ \mathrm{HCl}/ 273\mathrm{K}, \left(\mathrm{ii}\right) {\mathrm{H}}_3{\mathrm{PO}}_2+ {\mathrm{H}}_2\mathrm{O}}{\to }} \mathrm{Z}$

• C₆H₅CO₂H

• C₆H₅OH

• C₆H₅CHO

• C₆H₆