General Organic Chemistry & Isomerism · JEE Main previous year questions

The number of chiral carbons in chloramphenicol is

An organic compound 'A' is oxidized with ${\text{Na}}_2{\text{O}}_2$ followed by boiling with ${\text{HNO}}_3$. The resultant solution is then treated with ammonium molybdate to yield a yellow precipitate. Based on above observation, the element present in the given compound is:

1. A.Fluorine
2. B.Phosphorus
3. C.Nitrogen
4. D.Sulphur

The correct sequence of thermal stability of the following carbonates is :

1. A.${\text{BaCO}}_3<{\text{SrCO}}_3<{\text{CaCO}}_3<{\text{MgCO}}_3$
2. B.${\text{MgCO}}_3<{\text{CaCO}}_3<{\text{SrCO}}_3<{\text{BaCO}}_3$
3. C.${\text{BaCO}}_3<{\text{CaCO}}_3<{\text{SrCO}}_3<{\text{MgCO}}_3$
4. D.${\text{MgCO}}_3<{\text{SrCO}}_3<{\text{CaCO}}_3<{\text{BaCO}}_3$

1. A.$120^{\circ }$
2. B.$58^{\circ }$
3. C.$151^{\circ }$
4. D.$149^{\circ }$

An 'Assertion' and a 'Reason' are given below. Choose the correct answer from the following options : Assertion (A) : Vinyl halides do not undergo nucleophilic substitution easily. Reason (R) : Even though the intermediate carbocation is stabilized by loosely held p-electrons, the cleavage is difficult because of strong bonding.

1. A.Both (A) and (R) are correct statements but (R) is not the correct explanation of (A)
2. B.Both (A) and (R) are correct statements and (R) is the correct explanation of (A)
3. C.(A) is correct statement but (R) is a wrong statement
4. D.Both (A) and (R) are wrong statements.

1. A.3, 5-dimethyl-4-propylhept-1-en-6-yne
2. B.3-methyl-4-(3-methylprop-1-enyl)-1-heptyne
3. C.3-methyl-4-(1-methylprop-2-enyl)-1-heptene
4. D.3,5-dimethyl-4-propylhept-6-en-1-yne

The principle of column chromatography is :

1. A.Gravitational force.
2. B.Capillary action.
3. C.Differential adsorption of the substances on the solid phase.
4. D.Differential absorption of the substances on the solid phase.

1. A.III < II < I
2. B.III < I < II
3. C.II < I < III
4. D.I < III < II

In chromatography, which of the following statements is incorrect for ${\mathrm{R}}_{\mathrm{f}}$ ?

1. A.${\mathrm{R}}_{\mathrm{f}}$ value depends on the type of chromatography.
2. B.Higher ${\mathrm{R}}_{\mathrm{f}}$ value means higher adsorption.
3. C.${\mathrm{R}}_{\mathrm{f}}$ value is dependent on the mobile phase.
4. D.The value of ${\mathrm{R}}_{\mathrm{f}}$ can not be more than one.

Which of these factors does not govern the stability of a conformation in acyclic compounds?

1. A.Angle strain
2. B.Torsional strain
3. C.Electrostatic forces of interaction
4. D.Steric interactions

The increasing order of nucleophilicity of the following nucleophiles is : (a) $\mathrm{C}{\mathrm{H}}_3\mathrm{C}{\mathrm{O}}_2^{-}$ (b) ${\mathrm{H}}_2\mathrm{O}$ (c) $\mathrm{C}{\mathrm{H}}_3\mathrm{S}{\mathrm{O}}_3^{-}$ (d) $\overline{\mathrm{O}}\mathrm{H}$

1. A.(b) < (c) < (a) < (d)
2. B.(b) < (c) < (d) < (a)
3. C.(a) < (d) < (c) < (b)
4. D.(d) < (a) < (c) < (b)

The organic compound that gives following qualitative analysis is : $$\begin{array}{lll}& \text{Test}& \text{Inference}\\ \text{(a)}& \text{Dil. HCl}& \text{Insoluble}\\ \text{(b)}& \text{NaOH solution}& \text{soluble}\\ \text{(c)}& \mathrm{B}{\mathrm{r}}_2\text{/water}& \text{Decolourization}\end{array}$$

1. A.${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{OH}$ (phenol)
2. B.${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{N}{\mathrm{H}}_2$ (aniline)
3. C.${\mathrm{C}}_6{\mathrm{H}}_{11}\mathrm{N}{\mathrm{H}}_2$ (cyclohexylamine)
4. D.${\mathrm{C}}_6{\mathrm{H}}_{11}\mathrm{OH}$ (cyclohexanol)

The correct IUPAC name of the following compound is : [Benzene ring with $\mathrm{N}{\mathrm{O}}_2$ at one position, $\mathrm{C}{\mathrm{H}}_3$ para to $\mathrm{N}{\mathrm{O}}_2$, and Cl ortho to $\mathrm{C}{\mathrm{H}}_3$ (meta to $\mathrm{N}{\mathrm{O}}_2$)]

1. A.2-methyl-5-nitro-1-chlorobenzene
2. B.2-chloro-1-methyl-4-nitrobenzene
3. C.3-chloro-4-methyl-1-nitrobenzene
4. D.5-chloro-4-methyl-1-nitrobenzene

The increasing order of reactivity of the following compounds towards aromatic electrophilic substitution reaction is : A: ${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{Cl}$, B: ${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{OMe}$, C: ${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{Me}$, D: ${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{CN}$

1. A.A < B < C < D
2. B.D < A < C < B
3. C.D < B < A < C
4. D.B < C < A < D

The correct statement about $\mathrm{IC}{\mathrm{l}}_5$ and $\mathrm{IC}{\mathrm{l}}_4^{-}$ is

1. A.$\mathrm{IC}{\mathrm{l}}_5$ is square pyramidal and $\mathrm{IC}{\mathrm{l}}_4^{-}$ is square planar.
2. B.$\mathrm{IC}{\mathrm{l}}_5$ is trigonal bipyramidal and $\mathrm{IC}{\mathrm{l}}_4^{-}$ is tetrahedral.
3. C.$\mathrm{IC}{\mathrm{l}}_5$ is square pyramidal and $\mathrm{IC}{\mathrm{l}}_4^{-}$ is tetrahedral
4. D.Both are isostructural.

1. A.
2. B.
3. C.
4. D.

Which of the following complexes will show geometrical isomerism ?

1. A.aquachlorobis (ethylenediamine) cobalt (II) chloride
2. B.pentaaquachlorochromium (III) chloride
3. C.potassium amminetrichloroplatinate (II)
4. D.potassium tris(oxalato) chromate (III)

1. A.4-methyl-3-ethylhex-4-ene
2. B.3-ethyl-4-methylhex-4-ene
3. C.4-ethyl-3-methylhex-2-ene
4. D.4, 4- diethyl-3-methylbut-2-ene

When metal ‘M’ is treated with NaOH, a white gelatinous precipitate ‘X’ is obtained, which is soluble in excess of NaOH. Compound ‘X’ when heated strongly gives an oxide which is used in chromatography as an adsorbent. The metal ‘M’ is

1. A.Fe
2. B.Zn
3. C.Ca
4. D.Al

1. A.III
2. B.I
3. C.I and III
4. D.III and IV

Which of the following statements is not true about partition chromatography?

1. A.Mobile phase can be a gas
2. B.Stationary phase is a finely divided solid adsorbent
3. C.Separation depends upon equilibration of solute between a mobile and a stationary phase
4. D.Paper chromatography is an example of partition chromatography

1. A.1, 1-Dimethyl-2-ethylcyclohexane
2. B.2-Ethyl-1, 1-dimethylcyclohexane
3. C.1-Ethyl-2,2-dimethylcyclohexane
4. D.2, 2-Dimethyl-1-ethylcyclohexane

The distillation technique most suited for separating glycerol from spent-lye in the soap industry is :

1. A.Simple distillation
2. B.Fractional distillation
3. C.Steam distillation
4. D.Distillation under reduced pressure

Which of the following compounds will exhibit geometrical isomerism?

1. A.3-Phenyl-1-butene
2. B.2-Phenyl-1-butene
3. C.1,1-Diphenyl-1-propene
4. D.1-Phenyl-2-butene

For the estimation of nitrogen, 1.4 g of organic compound was digested by Kjeldahl method and the evolved ammonia was absorbed in 60 mL of M/10 sulphuric acid. The unreacted acid required 20 ml of M/10 sodium hydroxide for complete neutralization. The percentage of nitrogen in the compound is:

1. A.3%
2. B.5%
3. C.6%
4. D.10%