Recent questions tagged ch12

Which of the following is most stable

asked Mar 3, 2014 by meena.p

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A compound with empirical formula $CH_2O$ has a vapour density of 30. Its molecular formula is

asked Mar 3, 2014 by meena.p

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Which of the following is least reactive in a nucleophilic substitution reaction ?

asked Mar 3, 2014 by meena.p

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$CH_3Br +Nu^{-} \longrightarrow CH_3 -Nu +Br^{-} $ The decreasing order of the rate of the above reaction with nucleophiles $(NU)$ A to D is $[Nu^{-}=\quad (A)\; Pho^{-},\;(B)\;AcO^- ,\; (C)\; HO^{-},\; (D)\;CH_3O^{-}]$

asked Mar 3, 2014 by meena.p

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Which of the following compounds does not show lassaigne's test for nitrogen ?

asked Mar 3, 2014 by meena.p

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The enolic form of acetone contains

asked Mar 3, 2014 by meena.p

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For which of the following parameters the structural isomers $C_2H_5OH$ and $CH_3OCH_3$ would be expected to have the same values ? (Assume ideal behaviour )

asked Mar 3, 2014 by meena.p

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An enantiometrically pure acid is treated with racemix mixture of an alcohol having carbon. The ester formed will be :

asked Feb 28, 2014 by meena.p

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$CH_3,NH_2,OH$ and $F$ in increasing $pk_b $ values are :

asked Feb 28, 2014 by meena.p

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What is the decreasing order of strength of the bases. $OH^{-}.NH_2^{-}.HC \equiv C^{-}$ and $CH_3 -CH_2^{-} $?

asked Feb 28, 2014 by meena.p

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$CH_2 =CH CH_2CH =CH_2 \longrightarrow A,\;A $ is ?

asked Feb 28, 2014 by meena.p

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Br has a low reactivity in $CH_2 =CH-Br$ because (i) of -M effect of bromine (ii) of more electro negativity of bromine (iii) of partial double bond character between $C-Br $ bond. (iv) of the +M effect of bromine.

asked Feb 28, 2014 by meena.p

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Hydrolysis of neopentyl bromide under $SN_1$ process results into

asked Feb 28, 2014 by meena.p

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Which of the following is purified by vacuum distillation ? (i) Glycerine (ii) Glycerol (iii) propane 1,2,3- triol (iv) Ethanol

asked Feb 28, 2014 by meena.p

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Isomers which can not be interconverted through rotation around a single bond are : (i) Conformers ; (ii) diastereomers ; (iii) Enantiomers ; (iv) Positional isomers;

asked Feb 28, 2014 by meena.p

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The cannizzaro reaction of benzaldehyde and formaldehyde in the presence of $NaOH$ gives, $(i)\;C_6H_5CH_2OH\; ;(ii)\; C_6H_5COONa\; ; (iii)\; HCOONa \; ; (iv) \;CH_3OH$

asked Feb 28, 2014 by meena.p

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Which of the following compounds will have only primary and tertiary carbon? (i) Pentane (ii) 2- Methylbutane (iii) 2,3 -Dimethylbutane (iv) 2- Bromo-2-Methylpropane

asked Feb 28, 2014 by meena.p

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Which of the following have zero dipole moment ? $(i)\; H_2;\; (ii)\;HF;\; (iii)\; CH_4; \; (iv) CHCl_3$

asked Feb 28, 2014 by meena.p

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Which of the following statements are correct ?

asked Feb 28, 2014 by meena.p

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The statement which are correct regarding benzene are : (i) It has $12 \sigma$ and $3 \pi$ bonds. (ii) There is delocalisation of $\pi$ - electrons. (c) $C-C$ bond distance is $1.39 A^{\circ}$ . (d) $C-C$ bond distance is $1.39 A^{\circ}$ and $1.54\;A^{\circ}$ alternatively .

asked Feb 28, 2014 by meena.p

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Which of the following compounds are chiral and resolvable ? $(i) \;[C_6 H_5 N^+(CH_2CH_2CH_3)(C_2H_5)(CH_3)]Br^ - ; \; (ii) C_6H_5N(CH_3)(C_2H_5) ; \\ (iii)\; CH_3CH_2CH (CH_3) (C_2H_5);\; (iv)\; HO_2C- CO_2H$

asked Feb 28, 2014 by meena.p

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Which of the following will undergo a connizzara reaction ?

asked Feb 28, 2014 by meena.p

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In the reaction

asked Feb 28, 2014 by meena.p

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Which of the following groups are the following groups are ortho, para directing ? $ \\ (i) -NH_2 \quad\quad\quad (ii)\; -N-C -CH_3 \quad\quad\quad (iii)\;-CN \quad\quad\quad(iv)\; -SO_3H$

asked Feb 28, 2014 by meena.p

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Which of the following statement are true for the organoborance ? (i) It can be thermally rearranged (ii) It can be oxidised to 3-pentanol (iii) It can be converted to pentane (iv) None of these.

asked Feb 28, 2014 by meena.p

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Kjeldahl's method cannot be used for estimation of nitrogen in $(i)\; C_6H_5NO_2 ;\; (ii)\;Pyridine; \;(iii)\;C_6H_5 - N = N -C_6H_5 ;\;(iv)\;C_6H_5NHCOCH_3 $

asked Feb 28, 2014 by meena.p

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The molecules that will have dipole moments are : (i) 2,2 Dimethyl propane (ii) trans-2-pentene (iii) cis - 3 - Hexene (d) 2,2,3,3 -Tetramethyl butane

asked Feb 27, 2014 by meena.p

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When a carbon atom is linked to four different groups it is said to be chiral carbon atom. when alpha hydrogen atom of an alkane is replaced by a functional group we get corresponding compound.An optically active hydrocarbon $(A) C_6H_{10}$ on catalytic reduction gives optically inactive hydrocarbon . structure of $(A )$ is

asked Feb 27, 2014 by meena.p

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When a carbon atom is linked to four different groups it is said to be chiral carbon atom. when alpha hydrogen atom of an alkane is replaced by a functional group we get corresponding compound. IUPAC name for lowest molecular mas optically active alkene is

asked Feb 27, 2014 by meena.p

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When a carbon atom is linked to four different groups it is said to be chiral carbon atom. when alpha hydrogen atom of an alkane is replaced by a functional group we get corresponding compound. Lowest molecular mass optically active ketone contians ____ carbon atoms?

asked Feb 27, 2014 by meena.p

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When a carbon atom is linked to four different groups it is said to be chiral carbon atom. when alpha hydrogen atom of an alkane is replaced by a functional group we get corresponding compound. How many isomeric alkenes on catalytic reduction gives 3- methylhexane ?

asked Feb 27, 2014 by meena.p

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When a carbon atom is linked to four different groups it is said to be chiral carbon atom. when alpha hydrogen atom of an alkane is replaced by a functional group we get corresponding compound. How many C- atoms are present in lowest molecular mass optically active alkane?

asked Feb 27, 2014 by meena.p

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Optical and isomers are compounds which contain the same number and kinds of atoms, and bonds (ie the connectivity between atoms is the same), and different spatial arrangements of the atoms, but which have non-super imposable mirror images. Each non-super imposable mirror image structure is called an enantiomer. Optical isomers get their name because the plane – polarized light that is passed through a sample of a pure enantiomers is rotated. The planeis rotated in the opposite direction but with the same magnitude when plane- polarized light is passed through a pure sample containing the other enantiomer of a pair. A solution of one enantiomer rotates the plane of polrisation in a clockwise direction. This enantiomer is known as the (+) form. A solution of the other enantiomer rotales the plane of polarisation in an anti-clockwise direction. This enantiomer is known as (-) form.

asked Feb 27, 2014 by meena.p

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Optical and isomers are compounds which contain the same number and kinds of atoms, and bonds (ie the connectivity between atoms is the same), and different spatial arrangements of the atoms, but which have non-super imposable mirror images. Each non-super imposable mirror image structure is called an enantiomer. Optical isomers get their name because the plane – polarized light that is passed through a sample of a pure enantiomers is rotated. The planeis rotated in the opposite direction but with the same magnitude when plane- polarized light is passed through a pure sample containing the other enantiomer of a pair. A solution of one enantiomer rotates the plane of polrisation in a clockwise direction. This enantiomer is known as the (+) form. A solution of the other enantiomer rotales the plane of polarisation in an anti-clockwise direction. This enantiomer is known as (-) form.

asked Feb 27, 2014 by meena.p

1 answer

Optical and isomers are compounds which contain the same number and kinds of atoms, and bonds (ie the connectivity between atoms is the same), and different spatial arrangements of the atoms, but which have non-super imposable mirror images. Each non-super imposable mirror image structure is called an enantiomer. Optical isomers get their name because the plane – polarized light that is passed through a sample of a pure enantiomers is rotated. The planeis rotated in the opposite direction but with the same magnitude when plane- polarized light is passed through a pure sample containing the other enantiomer of a pair. A solution of one enantiomer rotates the plane of polrisation in a clockwise direction. This enantiomer is known as the (+) form. A solution of the other enantiomer rotales the plane of polarisation in an anti-clockwise direction. This enantiomer is known as (-) form.

asked Feb 27, 2014 by meena.p

1 answer

Optical and isomers are compounds which contain the same number and kinds of atoms, and bonds (ie the connectivity between atoms is the same), and different spatial arrangements of the atoms, but which have non-super imposable mirror images. Each non-super imposable mirror image structure is called an enantiomer. Optical isomers get their name because the plane – polarized light that is passed through a sample of a pure enantiomers is rotated. The planeis rotated in the opposite direction but with the same magnitude when plane- polarized light is passed through a pure sample containing the other enantiomer of a pair. A solution of one enantiomer rotates the plane of polrisation in a clockwise direction. This enantiomer is known as the (+) form. A solution of the other enantiomer rotales the plane of polarisation in an anti-clockwise direction. This enantiomer is known as (-) form.

asked Feb 27, 2014 by meena.p

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Ketanol tautomerism refers to a chemical equilibrium between a keto form (a ketone or an aldehyde) and an enol. The enol and keto fprms are said to be tatutomers of each other. The interconversion of the two forms involved the movements of a proton and the shifting of bonding electrons. A compound containing a carbonyl group $(C=0)$ is normally in rapid equilibrium with an enol tautomer, which contains a pair of doubly bonded carbon atoms adjacent to a hydroxyl $(-OH)$ group, $C=C-OH$ For a carbonyl compound to exhibit tautomerism, the essential condition is that, it must have at least one $ \alpha -H$ atom. Generally , the keto form is more stable than the enol form due to the greater strength of the carbon- oxygen $\pi$ bond as compared - carbon $\pi$ bond. In keto-enol tautomerism of dicarbonyl compounds, the enol form is preferred in contrast to the keto- form , this is due toMaximum enol content is observed in

asked Feb 27, 2014 by meena.p

1 answer

Which of the following organic compound shows Keto–enol tautomerism?

asked Feb 27, 2014 by meena.p

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Ketanol tautomerism refers to a chemical equilibrium between a keto form (a ketone or an aldehyde) and an enol. The enol and keto fprms are said to be tatutomers of each other. The interconversion of the two forms involved the movements of a proton and the shifting of bonding electrons. A compound containing a carbonyl group $(C=0)$ is normally in rapid equilibrium with an enol tautomer, which contains a pair of doubly bonded carbon atoms adjacent to a hydroxyl $(-OH)$ group, $C=C-OH$ For a carbonyl compound to exhibit tautomerism, the essential condition is that, it must have at least one $ \alpha -H$ atom. Generally , the keto form is more stable than the enol form due to the greater strength of the carbon- oxygen $\pi$ bond as compared - carbon $\pi$ bond. Keto- enol tatutomerism is observed in

asked Feb 26, 2014 by meena.p

1 answer

Ketanol tautomerism refers to a chemical equilibrium between a keto form (a ketone or an aldehyde) and an enol. The enol and keto fprms are said to be tatutomers of each other. The interconversion of the two forms involved the movements of a proton and the shifting of bonding electrons. A compound containing a carbonyl group $(C=0)$ is normally in rapid equilibrium with an enol tautomer, which contains a pair of doubly bonded carbon atoms adjacent to a hydroxyl $(-OH)$ group, $C=C-OH$ For a carbonyl compound to exhibit tautomerism, the essential condition is that, it must have at least one $ \alpha -H$ atom. Generally , the keto form is more stable than the enol form due to the greater strength of the carbon- oxygen $\pi$ bond as compared - carbon $\pi$ bond. In keto-enol tautomerism of dicarbonyl compounds, the enol form is preferred in contrast to the keto- form , this is due to

asked Feb 26, 2014 by meena.p

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The stability of carbanions in the following :

asked Feb 26, 2014 by meena.p

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The most unlikely representation of resonance structure of P-nitrophenoxide ion is

asked Feb 26, 2014 by meena.p

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Increasing order of stability among the three main conformation (ie eclipse, anti, gauche) of 2- fluoroethanol is

asked Feb 26, 2014 by meena.p

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For $(i) I^-, (ii) Cl^{-}, (iii) Br^{-} $. The increasing order of nuclephilicity would be :

asked Feb 26, 2014 by meena.p

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Which of the following is the correct order of decreasing $SN_2$ reactivity :

asked Feb 26, 2014 by meena.p

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The order of decreasing stability of the carbanions $(CH_3)_3 C^-(I) ; (CH_3)_2CH^{-1}(II) ; CH_3CH_2^{-}(III); C_6H_5CH_2^{-} (IV)$ is

asked Feb 26, 2014 by meena.p

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If two compounds have same empirical formula but different molecular formulae, they must have,

asked Feb 26, 2014 by meena.p

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Which of the following conformations cyclohexane is chiral?

asked Feb 26, 2014 by meena.p

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Which of the following alkenes will react fastest with $H_2$ under catalytic hydrogenation conditions ?

asked Feb 26, 2014 by meena.p

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Which of the following compounds possesses the $C-H$ bond with the lowest bond dissocation energy :

asked Feb 26, 2014 by meena.p

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