39Haloalkanes (Alkyl halides)

📚
GENERAL METHODS OF PREPARATION OF ALKYL HALIDES
▢ From Alkanes:
❖ Direct Halogenation:
  • •
    \(R-H + X_2 \xrightarrow{h\nu/\Delta/catalyst} R-X + HX\), \(X = Cl, Br, I\)
  • •
    Mechanism → free-radical substitution
  • •
    Product → mixture: mono + polyhalogen derivatives
  • •
    Laboratory use → poor; separation difficult
  • •
    Commercial use → important; petroleum/natural gas source
  • •
    Excess alkane → monosubstituted product major
❖ Example:
  1. \(CH_4 + Cl_2 \xrightarrow{h\nu/250-400^\circ C} CH_3Cl + CH_2Cl_2 + CHCl_3 + CCl_4 + HCl\)
  2. \(CH_3CH_3 + Cl_2 \xrightarrow{h\nu/250-400^\circ C} CH_3CH_2Cl + HCl\) → ethyl chloride major

Table 1: Reactivity Orders

Basis
Order
Reason/Note
Alkane
\(3^\circ > 2^\circ > 1^\circ\)
radical stability
Halogen
\(F_2 > Cl_2 > Br_2 > I_2\)
reactivity ↓ down group
Fluorination
very vigorous
C-C rupture in higher alkanes
Chlorination
fast
less selective
Bromination
slow
more selective
Iodination
not direct
reversible + highly endothermic
❖ Fluorination:
◉ Problem: Too reactive → C-C rupture
◉ Preparation: Halide exchange reactions
◉ Swarts Reaction:
  • •
    Alkyl chloride + inorganic fluoride → alkyl fluoride
  • •
    \(R-Cl + AgF \rightarrow R-F + AgCl\)
  • •
    \(R-Cl + Hg_2F_2 \rightarrow R-F + Hg_2Cl_2\)
  • •
    \(3R-Cl + AsF_3 \rightarrow 3R-F + AsCl_3\)
  • •
    \(3R-Cl + SbF_3 \rightarrow 3R-F + SbCl_3\)
◉ Important Fluorides:
  1. \(AgF\)
  2. \(Hg_2F_2\)
  3. \(AsF_3\)
  4. \(SbF_3\)
❖ Iodination:
◉ Direct Reaction: \(R-H + I_2 \rightleftharpoons R-I + HI\)
◉ Driving Agents:
  1. conc. \(HNO_3\)
  2. iodic acid \(HIO_3\)
◉ Oxidation of HI: \(5HI + HIO_3 \rightarrow 3I_2 + 3H_2O\)
◉ Methane: iodination → absent
◉ Finkelstein Reaction:
  • •
    Only iodoalkanes obtained
  • •
    Cl/Br displaced by \(I^-\)
  • •
    \(R-Cl + NaI \xrightarrow{acetone,\Delta} R-I + NaCl\)
  • •
    \(R-Br + NaI \xrightarrow{acetone,\Delta} R-I + NaBr\)
▢ From Alkenes:
❖ Addition of Halogen Acids:
  • •
    \(CH_2=CH_2 + HI \rightarrow CH_3CH_2I\)
  • •
    \(CH_2=CH_2 + HBr \rightarrow CH_3CH_2Br\)
  • •
    \(CH_2=CH_2 + HCl \rightarrow CH_3CH_2Cl\)
  • •
    \(CH_2=CH_2 + HF \rightarrow CH_3CH_2F\)
❖ HX Reactivity: \(HI > HBr > HCl > HF\)

Table 1: Markownikoff vs Anti-Markownikoff Addition

Feature
Markownikoff Addition
Anti-Markownikoff Addition / Kharasch Effect / Peroxide Effect
Condition
All HX; except \(HBr\) + peroxide
Only \(HBr\) + peroxide \((C_6H_5COO)_2\)
Rule
negative part → C with less H
negative part → C with more H
Memory
धनिक को धनिक बनाउ
Reaction Type
electrophilic addition
free-radical addition
Intermediate
carbocation
free radical
Shift
1,2-hydride/alkyl shift possible
no hydride/methyl shift
Example
\(CH_3CH=CH_2 + HBr \rightarrow CH_3CHBrCH_3\) → 2-bromopropane
\(CH_3CH=CH_2 + HBr \xrightarrow{peroxide} CH_3CH_2CH_2Br\) → 1-bromopropane
❖ Carbocation Rearrangement:
  • •
    Less stable carbocation → more stable carbocation
  • •
    Mode → 1,2-hydride shift / 1,2-alkyl shift
  • •
    Example: 3-methylbut-1-ene + HBr → 2-bromo-2-methylbutane
  • •
    Reason → \(2^\circ\) carbocation → \(3^\circ\) carbocation
▢ From Alcohols:
❖ Principle: \(R-OH + HX \rightarrow R-X + H_2O\) → replacement of \(-OH\) by halogen; SN reaction
❖ Action of HX:
◉ Groove Process: \(R-OH + conc.\ HCl(g) \xrightarrow{anhyd.\ ZnCl_2} R-Cl + H_2O\)
◉ Lucas Reagent: conc. \(HCl\) + anhyd. \(ZnCl_2\) = 1:1
◉ Function of \(ZnCl_2\): coordinates with alcohol O → C-O cleavage ↑
◉ Alcohol Reactivity: \(3^\circ > 2^\circ > 1^\circ\)
◉ HX Reactivity: \(HI > HBr > HCl\)
◉ Mechanism:
  • •
    \(1^\circ\) alcohol → \(SN2\)
  • •
    \(2^\circ,3^\circ\) alcohol → \(SN1\)
  • •
    \(3^\circ\) alcohol + HCl → no \(ZnCl_2\) required
❖ Action of Phosphorus Halides:
  • •
    \(3R-OH + PCl_3 \rightarrow 3R-Cl + H_3PO_3\)
  • •
    \(R-OH + PCl_5 \xrightarrow{\Delta} R-Cl + POCl_3 + HCl\)
  • •
    Bromo/iodoalkanes: \(PBr_3\)/\(PI_3\) generated in situ by red P + \(Br_2/I_2\)
  • •
    \(3R-OH + PBr_3 \rightarrow 3R-Br + H_3PO_3\)
  • •
    \(3R-OH + PI_3 \rightarrow 3R-I + H_3PO_3\)
  • •
    Yield → good for \(1^\circ\); poor for \(2^\circ/3^\circ\) due to alkene formation on heating
❖ Darzen Method:
  • •
    \(R-OH + SOCl_2 \xrightarrow{pyridine,reflux} R-Cl + SO_2\uparrow + HCl\uparrow\)
  • •
    Best method for chloroalkanes
  • •
    By-products gaseous → escape → purity ↑
  • •
    Bromides/iodides not prepared: \(SOBr_2\) unstable; \(SOI_2\) does not exist
▢ From Ethers:
❖ General Reaction: \(R-O-R' + 2HX \xrightarrow{\Delta} R-X + R'-X + H_2O\)
❖ Example: \(C_2H_5-O-CH_3 + 2HCl \xrightarrow{\Delta} C_2H_5Cl + CH_3Cl + H_2O\)
▢ Borodine-Hunsdiecker / Hunsdiecker Reaction:
❖ Reaction: \(RCOOAg + Br_2 \xrightarrow{CCl_4,reflux} RBr + CO_2 + AgBr\)
❖ Example: \(CH_3COOAg + Br_2 \xrightarrow{CCl_4} CH_3Br + CO_2 + AgBr\)
❖ Key Points:
  • •
    Silver salt of carboxylic acid + bromine
  • •
    Mechanism → free radical
  • •
    Carbon chain ↓ by 1 → descent of series
  • •
    Yield of alkyl bromide → low/slow
  • •
    Yield order → \(1^\circ > 2^\circ > 3^\circ\)
  • •
    Bromides → good yield
  • •
    Chlorides → very low yield
  • •
    Iodides → not obtained; esters formed
❖ Birnbaum-Simonini Reaction:
  1. \(2RCOOAg + I_2 \rightarrow RCOOR + CO_2 + 2AgI\)
  2. \(2CH_3COOAg + I_2 \rightarrow CH_3COOCH_3 + CO_2 + 2AgI\)
📚
PROPERTIES OF ALKYL HALIDES
📖
Physical properties

Table 1: Melting/Boiling Point

Basis
Order/Rule
Reason
Molecular mass
molecular mass ↑ → mp/bp ↑
Van der Waals force ↑
Same alkyl group
\(RI > RBr > RCl > RF\)
halogen atomic mass ↑
Same halogen
\(CH_3CH_2CH_2X > CH_3CH_2X > CH_3X\)
alkyl size ↑
Branching
straight chain > branched
surface area ↓ with branching
Isomeric chlorobutanes
\(CH_3CH_2CH_2CH_2Cl > CH_3CH_2CHClCH_3 > (CH_3)_2CHCH_2Cl > (CH_3)_3CCl\)
branching ↑ → bp ↓
Dichlorobenzenes
p-isomer mp > o-/m-isomer
symmetry + close packing + lattice energy ↑

Table 2: Density, Bond Strength, Dipole Moment, Stability

Property
Order
Note
Density: same alkyl/aryl
\(RI > RBr > RCl > RF\)
halogen mass ↑
Density: same halogen
\(CH_3I > C_2H_5I > C_3H_7I\)
alkyl size ↑ → density ↓
C-X bond strength
\(CH_3F > CH_3Cl > CH_3Br > CH_3I\)
\(\propto 1/\) size of halogen
Dipole moment
\(CH_3Cl > CH_3F > CH_3Br > CH_3I\)
F small size offsets high electronegativity
Stability
\(R-F > R-Cl > R-Br > R-I\)
C-X bond strength ↓
Alkyl iodide decomposition
\(2R-I \xrightarrow{sunlight} R-R + I_2\)
\(I_2\) → violet/brown colour

Table 3: HX / Halide Order Summary

Property
Order
Thermal strength
\(HF > HCl > HBr > HI\)
Bond polarity
\(HF > HCl > HBr > HI\)
Dipole moment
\(HF > HCl > HBr > HI\)
Ionic character of metal halides
\(MF > MCl > MBr > MI\)
Boiling point
\(HF > HI > HBr > HCl\)
Reactivity
\(HI > HBr > HCl > HF\)
Acidic strength
\(HI > HBr > HCl > HF\)
Reducing nature
\(HI > HBr > HCl > HF\)
▢ Solubility:
  • •
    Alkyl/aryl halides → insoluble in water
  • •
    Reason → no H-bond with water
▢ p-Dichlorobenzene Note:
  • •
    Symmetrical → close crystal packing
  • •
    Lattice energy ↑ → melting point ↑
  • •
    Solubility ↓ in given solvent
  • •
    Separation feasible by fractional crystallization
📖
Chemical properties
▢ Reactivity:
  • •
    Polar \(C-X\) bond → high reactivity
  • •
    Polarity order: \(CH_3Cl > CH_3F > CH_3Br > CH_3I\)
  • •
    Expected reactivity: \(R-Cl > R-F > R-Br > R-I\)
  • •
    Actual reactivity: \(R-I > R-Br > R-Cl > R-F\)
  • •
    Reason → bond dissociation energy: \(C-F > C-Cl > C-Br > C-I\)
▢ Nucleophilic Substitution:

Table 1: \(SN1\) vs \(SN2\)

Feature
\(SN1\)
\(SN2\)
Molecularity
unimolecular
bimolecular
RDS
substrate only
substrate + nucleophile
Kinetics
1st order
2nd order
Steps
2-step / multistep
1-step
Intermediate
carbocation
transition state only
Stereochemistry
racemization: retention + inversion
Walden inversion / umbrella inversion
Substrate rate
\(3^\circ > 2^\circ > 1^\circ > CH_3X\)
\(CH_3X > 1^\circ > 2^\circ > 3^\circ\)
Reason
carbocation stability
steric hindrance + inductive effect
Solvent
polar protic: water
polar aprotic: acetone, DMSO, DMF
Nucleophile
weak; low concentration
strong; high concentration
Leaving group
weak base + polarizable → rate ↑
weak base + polarizable → rate ↑

Table 2: Common SN Replacements

Replacement
Reagent
Product
Reaction/Note
\(-OH\)
aq. \(NaOH/KOH\)
alcohol
\(R-X + aq.KOH \xrightarrow{\Delta} R-OH + KX\)
\(-OH\)
moist \(Ag_2O\) / \(AgOH\)
alcohol
\(R-X + AgOH \xrightarrow{\Delta} R-OH + AgX\)
\(-OR\)
\(NaOR'\)
ether
Williamson ether synthesis: \(R-X + NaOR' \rightarrow R-O-R' + NaX\)
\(-OR\)
dry \(Ag_2O\)
symmetrical ether
\(2R-X + Ag_2O \rightarrow R-O-R + 2AgX\)
\(-SH\)
\(NaSH\) in \(C_2H_5OH/H_2O\)
thioalcohol / mercaptan
\(R-X + NaSH \rightarrow R-SH + NaX\); ethyl mercaptan → LPG odour
\(-SR\)
\(Na_2S\)
dialkyl thioether
\(2R-X + Na_2S \rightarrow R-S-R + 2NaX\)
\(-SR'\)
\(NaSR'\)
alkyl alkyl' thioether
\(R-X + NaSR' \rightarrow R-S-R' + NaX\)
\(-NH_2\)
\(NH_3\)
amines + quaternary ammonium salt
successive alkylation

Table 3: Cyanide vs Isocyanide

Feature
Cyanide \((-CN)\)
Isocyanide \((-NC)\)
Product
alkyl cyanide / alkane nitrile
alkyl isocyanide / carbylamine / alkane isonitrile
Reagent
alc. \(KCN\)
alc. \(AgCN\)
Nucleophile
\(CN^-\)
\(NC^-\)
Attack through
C
N
Reaction
\(R-X + KCN \xrightarrow{alc.,\Delta} R-C\equiv N + KX\)
\(R-X + AgCN \xrightarrow{alc.,\Delta} R-N\equiv C + AgX\)
Complete hydrolysis
\(R-CN \rightarrow R-COOH\)
\(R-NC \rightarrow R-NH_2 + HCOOH\)
Reduction
\(R-CN \xrightarrow{LiAlH_4/Na-C_2H_5OH} R-CH_2NH_2\)
\(R-NC \xrightarrow{LiAlH_4/Na-C_2H_5OH} R-NHCH_3\)
Stephen reduction
\(R-CN \xrightarrow{SnCl_2/HCl} R-CHO\)
not useful

Table 4: Nitro vs Nitrite

Feature
Nitro \((-NO_2)\)
Nitrite \((-O-N=O)\)
Reagent
alc. \(AgNO_2\)
alc. \(KNO_2\)
Product
nitroalkane
alkyl nitrite
Example
\(CH_3Cl + AgNO_2 \xrightarrow{alc.,\Delta} CH_3NO_2 + AgCl\)
\(CH_3Cl + KNO_2 \xrightarrow{alc.,\Delta} CH_3ONO + KCl\)
❖ Amination Sequence:
  • •
    \(NH_3 \xrightarrow{+C_2H_5Br,-HBr} C_2H_5NH_2\) → 1° amine
  • •
    \(C_2H_5NH_2 \xrightarrow{+C_2H_5Br,-HBr} (C_2H_5)_2NH\) → 2° amine
  • •
    \((C_2H_5)_2NH \xrightarrow{+C_2H_5Br,-HBr} (C_2H_5)_3N\) → 3° amine
  • •
    \((C_2H_5)_3N \xrightarrow{+C_2H_5Br} [(C_2H_5)_4N]^+Br^-\) → quaternary ammonium salt
▢ Elimination Reaction:
❖ Definition: Alkyl halide + base → alkene + \(HX\) removed
❖ Type: \(\beta\)-elimination / E2 dehydrohalogenation
❖ Condition: trans-periplanar H and X → same plane + trans position
❖ General Reaction: \(R-CH_2-CH_2-X + alc.KOH \xrightarrow{\Delta} R-CH=CH_2 + H_2O + KX\)

Table 1: E2 Orders and Agents

Basis
Order/Agents
Alkyl group
\(3^\circ > 2^\circ > 1^\circ\)
Halide
\(R-I > R-Br > R-Cl > R-F\)
Agents
alc. KOH; \(NaNH_2\); \(CH_3OH+CH_3ONa\); \(C_2H_5OH+C_2H_5ONa\)

Table 2: Saytzeff vs Hofmann Product

Rule
Major Product
Meaning
Saytzeff
more substituted alkene
गरिब को गरिब बनाउ
Hofmann
less substituted alkene
minor product in usual dehydrohalogenation
Example
\(2\)-bromobutane + alc.KOH → but-2-ene major + but-1-ene minor
▢ Reaction with Metals:

Table 1: Metal Reactions

Metal/Reagent
Name/Product
General Reaction
Note
Li / dry ether
alkyl lithium
\(R-X + 2Li \xrightarrow{dry\ ether} R-Li + LiX\)
organolithium compound
Na / dry ether
Wurtz reaction
\(R-X + 2Na + X-R \xrightarrow{dry\ ether} R-R + 2NaX\)
methane cannot be prepared; mixed halides → 3 alkanes; free-radical mechanism
Mg / dry ether
Grignard reagent
\(R-X + Mg \xrightarrow{dry\ ether} R-MgX\)
alkyl magnesium halide
Zn / dry ether
Frankland reaction
\(R-X + Zn + X-R \xrightarrow{dry\ ether} R-R + ZnX_2\)
mixed halides → 3 alkanes
▢ Reduction:
  • •
    Catalytic: \(R-X + H_2 \xrightarrow{Ni/Pd/Pt,\Delta} R-H + HX\)
  • •
    Nascent H: \(LiAlH_4\), \(NaBH_4\), \(Na+C_2H_5OH\), Zn-Cu + alcohol, \(Zn+CH_3COOH\), \(Zn+NaOH\), \(Zn+HCl\), \(Sn+HCl\)
  • •
    HI/red P: \(R-X + HI \xrightarrow{red\ P,150^\circ C} R-H + HX\)
📚
GRIGNARD REAGENT
📖
Preparation
\(R-X + Mg \xrightarrow{dry\ ether} R-MgX\)
📖
Nature
  • •
    Highly reactive organomagnesium halide
  • •
    Destroyed by active H compounds
  • •
    Used for C-C bond formation
📖
Alkanes

Table 1: From Active Hydrogen Compounds

Substrate
Example Reaction
Product
Water
\(H-OH + C_2H_5MgBr \rightarrow C_2H_6 + Mg(OH)Br\)
alkane
Heavy water
\(D-OD + C_2H_5MgBr \rightarrow C_2H_5D + Mg(OD)Br\)
deuterated alkane
Alcohol
\(CH_3OH + C_2H_5MgBr \rightarrow C_2H_6 + Mg(OCH_3)Br\)
alkane
Thioalcohol
\(CH_3SH + C_2H_5MgBr \rightarrow C_2H_6 + Mg(SCH_3)Br\)
alkane
Phenol
\(C_6H_5OH + C_2H_5MgBr \rightarrow C_2H_6 + Mg(OC_6H_5)Br\)
alkane
Carboxylic acid
\(CH_3COOH + C_2H_5MgBr \rightarrow C_2H_6 + Mg(OOCCH_3)Br\)
alkane
Terminal alkyne
\(HC\equiv CH + C_2H_5MgBr \rightarrow C_2H_6 + Mg(C\equiv CH)Br\)
alkane + acetylide
Amine
\(CH_3NH_2 + C_2H_5MgBr \rightarrow C_2H_6 + Mg(NHCH_3)Br\)
alkane
Zerewitinoff method: 1 active H → 1 molecule alkane; estimation of \(-OH\), \(-NH_2\), \(-SH\), \(\equiv C-H\).

Table 2: From Alkyl Halides

Reaction
Example
Product
\(R-X + R'MgX \rightarrow R-R' + MgXX'\)
\(CH_3Cl + C_2H_5MgBr \rightarrow C_2H_5CH_3 + MgClBr\)
higher alkane
📖
Alkenes and alkynes
📝
Higher Alkene
\(CH_2=CH-CH_2Cl + C_2H_5MgBr \rightarrow CH_2=CH-CH_2-C_2H_5 + MgClBr\)
📝
Higher Alkyne
  1. \(HC\equiv CH + C_2H_5MgBr \rightarrow C_2H_6 + Mg(C\equiv CH)Br\)
  2. \(Mg(C\equiv CH)Br + CH_3I \rightarrow CH_3C\equiv CH + MgIBr\)
📖
Alkyl cyanides

Table 1: Preparation of Alkyl Cyanides

Substrate
Reaction
Product
Cyanogen
\(CN-CN + C_2H_5MgBr \rightarrow C_2H_5CN + Mg(CN)Br\)
ethyl cyanide
Cyanogen chloride
\(Cl-CN + C_2H_5MgBr \rightarrow C_2H_5CN + MgClBr\)
ethyl cyanide
📖
Alcohols

Table 1: Alcohol Synthesis by Grignard Reagent

Alcohol Type
Substrate
Product Rule
Example
Primary
oxygen
methyl Grignard → methanol
\(\frac{1}{2}O_2 + CH_3MgBr \rightarrow CH_3OMgBr \xrightarrow{H_2O} CH_3OH\)
Primary
ethylene oxide
\(+2C\) chain extension
ethylene oxide + \(CH_3MgBr\) → propyl alcohol
Primary
formaldehyde
\(R-CH_2OH\)
\(HCHO + CH_3MgBr \xrightarrow{H_2O/H^+} C_2H_5OH\)
Secondary
aldehyde except formaldehyde
\(R-CH(OH)-R'\)
acetaldehyde + \(CH_3MgBr\) → isopropyl alcohol
Secondary
formic ester + 2 eq. Grignard
\(R_2CHOH\)
ethyl formate + \(2CH_3MgBr\) → isopropyl alcohol
Tertiary
ketone
\(R_3COH\)
acetone + \(CH_3MgBr\) → tert-butyl alcohol
Tertiary
ester except formic ester + 2 eq. Grignard
\(R_3COH\)
ethyl acetate + \(2CH_3MgBr\) → tert-butyl alcohol
📖
Aldehydes

Table 1: Preparation of Aldehydes

Source
Condition
Product
Hydrogen cyanide
\(HCN + RMgX \rightarrow\) imine Mg salt \(\xrightarrow{H_2O/H^+}\)
aldehyde
Alkyl formate
equimolar Grignard reagent
aldehyde
Alkyl orthoformate
Grignard reagent → hydrolysis
aldehyde
Example
\(HCN + CH_3MgBr \xrightarrow{H_2O/H^+} CH_3CHO\)
acetaldehyde
📖
Ketones

Table 1: Preparation of Ketones

Source
Condition
Product/Note
Alkyl cyanide
equimolar Grignard
\(R-CN + R'MgX \xrightarrow{H_2O/H^+} R-CO-R'\)
Acid chloride
equimolar Grignard
\(RCOCl + R'MgX \rightarrow RCO-R' + MgClX\)
Acid anhydride
Grignard reagent
ketone
Amide
Grignard reagent
ketone
Excess Grignard
ketone reacts further
\(3^\circ\) alcohol final
📝
Examples
  1. \(CH_3CN + CH_3MgBr \xrightarrow{H_2O/H^+} CH_3COCH_3\) → acetone
  2. \(CH_3COCl + CH_3MgBr \rightarrow CH_3COCH_3 + MgClBr\)
  3. \((CH_3CO)_2O + CH_3MgBr \rightarrow CH_3COCH_3 + Mg(CH_3COO)Br\)
  4. \(CH_3CONH_2 + CH_3MgBr \rightarrow CH_3COCH_3 + Mg(NH_2)Br\)
📖
Carboxylic acids
📝
From Carbon Dioxide
\(CO_2 + RMgX \rightarrow RCOOMgX \xrightarrow{H_2O/H^+} RCOOH\)
📝
Example
\(CO_2 + CH_3MgBr \xrightarrow{H_2O/H^+} CH_3COOH\)
📖
Amines
📝
From Chloramine
\(Cl-NH_2 + C_2H_5MgBr \rightarrow C_2H_5NH_2 + MgClBr\)
📖
Other organometallic compounds

Table 1: Organometallic Products

Product
Reaction
Note
Tetraethyl lead
\(2PbCl_2 + 4C_2H_5MgBr \rightarrow (C_2H_5)_4Pb + MgClBr + Pb\)
antiknock agent
Tetraethyl silane
\(SiCl_4 + 4C_2H_5MgBr \rightarrow (C_2H_5)_4Si + MgClBr\)
organosilicon compound
Diethyl zinc
\(ZnCl_2 + 2C_2H_5MgBr \rightarrow (C_2H_5)_2Zn + MgClBr\)
organozinc compound
Q1.
When chloroform is boiled with aqueous KOH followed by acidification it gives [IOM 2008]
📅2008
Q2.
An alkyl halide can be converted into alcohol by [IOM 2008, IOM 2004]
📅2008•2004
Q3.
Chlorine reacts with Benzaldehyde to give [IOM 2063]
📅2063
Q4.
Tear gas is [IOM 2005]
📅2005
Q5.
Chloral is [MOE 2064]
📅2064
Q6.
The reaction between benzene diazonium chloride and CuCl₂/HCl is [Bangladesh Embassy, BPKIHS]
Q7.
The reaction between aniline and chloroform in presence of NaOH is called [Bangladesh Embassy]
Q8.
The purpose of using anhydrous AlCl₃ as a catalyst in Friedel-Crafts reaction is to [MOE 2053]
📅2053
Q9.
A sample of chloroform is tested by which of the following before being used as anaesthetic? [IOM 2053, 2054]
📅2053•2054
Q10.
Anaesthetic chloroform is always stored in yellow bottles filled up to stopper because [Indian Embassy]
Q11.
The compound which gives negative iodoform test is [BPKIHS]
Q12.
Chloroform is used for the test of ... amines [IOM 2004]
📅2004
Q13.
Chloretone is obtained by chemical reaction of [MOE]
Q14.
Chloroform reacts with nitric acid to form an insecticide called chloropicrin. Its formula is [MOE 2051]
📅2051
Q15.
Dehydro-halogenation of alkyl halide gives [MOE 2049]
📅2049
Q16.
The reaction C₆H₅NH₂ + CHCl₃ + KOH →(Alcoholic) C₆H₅NC + KCl is called [MOE, IOM 2051]
📅2051
Q17.
The reaction of benzene with haloalkane in presence of anhydrous AlCl₃ is [IOM 2054]
📅2054
Q18.
Which of the following compound is used in tear gas? [IOM 2051]
📅2051
📚
ADDITIONAL QUESTIONS
Q1.
Among the following compounds, the one with the highest percentage of chlorine is
Q2.
The order of reactivity of alkyl halides towards an SN2 reaction is
Q3.
Which of the following possesses highest melting point?
Q4.
Which of the following will have the maximum dipole moment?
Q5.
The order of reactivities of methyl halides in the formation of Grignard reagent is
Q6.
1-Chlorobutane when treated with alcoholic potash gives
Q7.
C2H5Cl + KCN → X → hydrolysis → Y. Compounds X and Y are
Q8.
Most reactive halide towards SN1 reaction is
Q9.
Which of the following alkyl halides is used as a methylating agent?
Q10.
The reactivity order of halides for dehydrohalogenation is
Q11.
The order of reactivity of alkyl halides towards elimination reaction is
Q12.
Which is not an organometallic compound?
Q13.
Formaldehyde gives an addition product with methyl magnesium iodide which on aqueous hydrolysis gives
Q14.
CO2 on reaction with ethyl magnesium bromide gives
Q15.
Chlorobenzene is prepared commercially by
Q16.
The reaction of C6H5N2+Cl- with CuCl gives
Q17.
Chlorobenzene on heating with aqueous NH3 under pressure in the presence of cuprous chloride gives
Q18.
The industrial preparation of chloroform employs acetone and
Q19.
CHCl3 on oxidation by air in presence of light gives
Q20.
AgNO3 does not give precipitate with chloroform because
Q21.
When ethylamine is heated with chloroform and alcoholic KOH, a compound with offensive smell is obtained. This compound is
Q22.
C2H5NC is known as
Q23.
Chloroform on warming with Ag powder gives
Q24.
When chloroform is treated with concentrated HNO3 it gives
Q25.
Chloropicrin is
Q26.
Chloropicrin is used as
Q27.
The final product formed by the hydrolysis of chloroform by aqueous KOH is
Q28.
When chloroform reacts with acetone the product is
Q29.
The following reaction is known as: Phenol → CHCl/NaOH → Salicylaldehyde
Q30.
Which of the following is an anaesthetic?
Q31.
Which of the following is known as freon?
Q32.
Which of the following is mainly responsible for depletion of ozone layer?
Q33.
Which of the following compounds is used as a refrigerant?
Q34.
Ethyl alcohol gives ethyl chloride with the help of
Q35.
Carbon tetrachloride reacts with C6H5OH and NaOH to form
Q36.
What happens when CCl4 is treated with AgNO3?
Q37.
Which of the following compounds is used as fire extinguisher?
Q38.
CCl4 is used as fire extinguisher because
Q39.
The pesticide DDT slowly changes to
Q40.
In which of the following p-electrons halogen are not involved in delocalisation?
Q41.
Aryl halides are less reactive toward nucleophilic substitution reaction as compared to alkyl halides due to
Q42.
The formula for freon-12 is
Q43.
Which of the following gives Iodoform test upon reaction with I2 and NaOH?
Q44.
Which is liquid at room temperature?
Q45.
When an alkyl halide is heated with dry Ag2O, it produces
Q46.
Allyl chloride on dehydrochlorination gives
Q47.
An organic compound which produces a bluish green coloured flame on heating in presence of copper is
Q48.
Ethylene oxide when treated with Grignard reagent yields
Q49.
The compound added to prevent chloroform from forming phosgene gas is
Q50.
Acetone is mixed with bleaching powder to give
Q51.
Which of the following gives trichloromethane on distilling with bleaching powder?
Q52.
Which reagent can convert butan-2-one to propanoic acid?
Q53.
Which of the following is formed when the product of oxidation of chloroform is treated with ethyl alcohol?
Q54.
Teflon polymer is formed by polymerisation of
Q55.
Which of the following is the most reactive in Grignard reagent formation?
Q56.
SN1 reaction of alkyl halides leads to
Q57.
A sample of chloroform being used as anesthetic is tested with
Q58.
At higher temperature iodoform reaction is given by
Q59.
C-CI bond is difficult to cleave in CH2=CH-Cl due to
Q60.
CCl4 is used in fire extinguishers under the name of
Q61.
SN2 mechanism proceeds through the formation of
Q62.
Both methane and ethane can be prepared in single step by the use of
Q63.
How many monochlorobutanes will be possible on chlorination of n-butane?
Q64.
Isopropyl chloride undergoes hydrolysis by
Q65.
SN1 reaction of alkyl halides causes racemization because of
Q66.
Vinyl chloride undergoes
Q67.
Tertiary alkyl halides are practically inert to substitution by SN2 mechanism because of
Q68.
Which of the following undergoes nucleophilic substitution exclusively by SN1 mechanism?
Q69.
Isoamyl halide is
Q70.
Which of the following reacts fastest with Lucas reagent?
Q71.
Which of the following is most reactive for halogenation?
Q72.
Which of the following reacts fastest in SN2?