What is inductive effect ? When a hetero atom of different electronegativities is attached to the ending carbon of a carbon   chain , then a permanent displacement of covalently bonded electrons  occurs  toward the more electronegative atom, which create a permanent polarization in molecule. So,inductive...

What is geometrical isomerism? Many compounds that contain one double bond exist in two forms which differ in most of their physical and in many of their chemical properties.  There is no free rotation about a double bond for such type of compounds due to maximum overlap of the two pi orbitals which cause resistance to...

What is resonance ? When a molecule can not be completely represented by a single structure but its characteristic properties can be described by two or more different structures , then the true structure is said to a resonance hybrid of these structure and this phenomenon is called resonance.      ...

What is charge transfer( CT ) or electron donor acceptor( EDA) complexes ? A charge transfer (CT) complex or electron donor acceptor (EDA) complex is an association of two or more molecules or different parts of one large molecule in which a fraction of electronic charge is transferred...

Why volume of ice decreases on melting ?  In ice , the water molecules are tetra hedrally oriented with respect to one another.At the same time each oxygen atom is surrounded tetra hedrally by four hydrogen atoms, two of these are bonded covalently and the other two by hydrogen bonds.  The hydrogen bonds...

What is elements of symmetry ? In stereo-chemistry, the elements of symmetry can be defined as a specific operations that generate the repetition of the geometric shapes of molecules which observed carrying out symmetry operation. What is simple or rotational axis of symmetry ?  Simple axis or...

What is racemic modification ? It has been observed that an equimolecular mixture of a pair of enantiomers is optically inactive.This is to expected,since enantiomers have equal but opposite rotatory power. Such type of a mixture is said to be optically inactive by external compensation and is known as a racemic modification.  It...

What is homotopic ? Two atoms or groups in a molecule are homotopic  if the separate replacement of each  group or atom  by some other group or atom produce the same molecule. For example, the  α-axial , β-axial and β-equitorial, α-equitorial H-atoms in chair conformation of cyclohexane are...

What is spirans ? If both double bonds in allene are replaced by ring systems, the resulting molecules are  called spirans. For example , spiro-2,2 pentane,  1-chloro spiro-5,3-nonane.  3D structure of 1-chloro-spiro-5,3-nonane is as follows. Why spirans are optically active ? Examination...

What is optical isomerism ? A compound which contains asymmetric carbon atom that  is, a carbon atom linked to four different groups or atoms, can exists in two isomeric forms which differ in their sign of rotation, such a compound exhibits optical isomerism.  For example, lactic acid . The 3D isomeric...