How many chain isomers could be obtained from the alkane C6 H14 ? 
Five chain isomers are possible which are –
Which of the following is an optically active compound ? 
The compound containing a chiral carbon atom i.e., (a carbon atom which is attached to four different substituents is known as a chiral carbon atom) is optically active.
The Cl – C – Cl angle in 1,1,2,2- tetrachloroethene and tetrachloromethane respectively will be about
Tetrachloroethene being an alkene has sp2 -hybridized C– atoms and hence the angle Cl – C – Cl is 120° while in tetrachloromethane, carbon is sp3 hybridized, therefore the angle Cl – C – Cl is 109.5°.
Which of the following possesses a sp-carbon in its structure ? 
Cyclic hydrocarbon ‘A’ has all the carbon and hydrogen atoms in a single plane. All the carbon carbon bonds have the same length, less than 1.54 Å, but more than 1.34 Å. The C – C – C bond angle will be 
All the properties mentioned in the question suggest that it is a benzene molecule. Since in benzene all carbons are sp2–hybridized, therefore, C – C – C angle is 120°
Lassaigne’s test is used in qualitative analysis to detect
Nitrogen, sulphur and halogens are tested in an organic compound by Lassaigne's test.
The organic compound is fused with sodium metal as to convert these elements into ionisable inorganic substances,
The cyanide, sulphide or halide ions can be confirmed in aqueous solution by usual test.
Which one of the following can exhibit cis-trans isomerism ? 
Such isomers, which possess the same molecular and structural formula but differ in the arrangement of atoms around the double bonded carbon atoms are known as geometrical isomers.
Kjeldahl’s method is used in the estimation of
Kjeldal's method is suitable for estimating nitrogen in those compounds in which nitrogen is linked to carbon and hydrogen.
The method is not used in case of nitro, azo and azoxy compound. This method is basically used for estimating nitrogen in food fertilizers and agricultural products.
An organic compound X (molecular formula C6H7O2N ) has six carbon atoms in a ring system, two double bonds and a nitro group as substituent, X is 
Hence it is homocyclic (as the ring system is made of one type of atoms, i.e. carbon) but not aromatic.As it does not have (4n +2)π electron required for aromaticity.
In sodium fusion test of organic compounds, the nitrogen of the organic compound is converted into
Sodium cyanide (Na + C + N → NaCN). (Lassaigne's test)
The shortest C – C bond distance is found in
Shortest C – C distance (1.20 Å) is in acetylene.
As acetylene has sp hybridisation, the bond length increases in the order
An sp3 hybrid orbital contains 
sp3 orbital has 1/4(25%) s-character. & 75% p character.
A straight chain hydrocarbon has the molecular formula C8H10. The hybridization of the carbon atoms from one end of the chain to the other are respectively sp3, sp2, sp2, sp3, sp2, sp2, sp and sp. The structural formula of the hydrocarbon would be : 
Isomers of a substance must have the same
Organic compounds having same molecular formula but differ from each other in physical properties or chemical properties or both are known as isomers.
Which of the following is the most stable carbocation (carboniumion) ? 
Higher the possibility of delocalisation of the positive charge, greater is stability of the species. Thus
Benzyl carbocation is more stable than tertbutyl due to resonance in the former.
A is a lighter phenol and B is an aromatic carboxylic acid. Separation of a mixture of A and B can be carried out easily by using a solution of
Carboxylic acids dissolve in NaHCO3 but phenols do not.
2-Methyl 2-butene will be represented as 
The IUPAC name of 
When the hybridization state of carbon atom changes from sp3 to sp2 and finally to sp, the angle between the hybridized orbitals 
Angle increases progressively sp3 ( 109°28' ), sp2 (120°), sp (180°)
The most reactive compound for electrophilic nitration is 
Due to + I-effect of the CH3 group, toluene has much higher electron density in the ring than benzene, nitrobenzene and benzoic acid as nitro and carboxylic group show- I-effect and hence toluene is most reactive towards nitration.
Which is the correct symbol relating the two Kekule structures of benzene ? 
Resonance structures are separated by a double headed arrow
The restricted rotation about carbon carbon double bond in 2-butene is due to 
Rotation around π bond is not possible. If any attempt is made to rotate one of the carbon atoms, the lobes of π-orbital will no longer remain coplanar i.e no parallel overlap will be possible and thus π-bond will break .
This is known as concept of restricted rotation. In other words the presence of π-bonds makes the position of two carbon atom.
An important chemical method to resolve a racemic mixture makes use of the formation of 
Diastereomers since they have different melting points, boiling points, solubilities etc.
The process of separation of a racemic modification into d and ℓ -enantiomers is called
Correct increasing order of acidity is as follows:
Such questions can be solved by considering the relative basic character of their conjugated bases which for H2O, C2H2, H2CO3 and C6H5OH are
More the possibility for the dispersal of the negative charge, weaker will be the base.
Thus the relative basic character of the four bases is
Thus the acidic character of the four corresponding acids wil be
An example of electrophilic substitution reaction is
Chlorination of methane proceeds via free radical mechanism. Conversion of methyl chloride to methyl alcohol proceeds via nucleophilic substitution. Formation of ethylene from ethyl alcohol proceeds via dehydration reaction. Nitration of benzene is electrophilic substitution reaction.
Which of the following IUPAC names is correct for the compound? 
Lassaigne’s test for the detection of nitrogen fails in
Hydrazine (NH2NH2) does not contain carbon and hence on fusion with Na metal, it cannot form NaCN; consequently hydrazine does not show Lassaigne’s test for nitrogen.
The most suitable method for separtion of a 1 : 1 mixture of ortho and para nitrophenols is 
The boiling point of o-nitrophenol is less than para-nitrophenol due to presence of intramolecular hydrogen bonding. Since p-nitrophenol is less volatile in than onitrophenol due to presence of inter molecular hydrogen bonding hence they can be separated by steam distillation.
The first organic compound, synthesized in the laboratory, was 
The vital force theory suffered first death blow in 1828 when Wohler synthesized the Ist organic compound urea in the laboratory from inorganic compounds reported below :
Later on a further blow to vital force theory was given by Kolbe (1845) who prepared acetic acid, the first organic compound, in laboratory from its elements.