Chemistry MCQs for NEET — Practice Questions with Answers

The NCERT text states, 'It is hindered by a small energy barrier of 1-20 kJ mol$^{-1}$ due to weak repulsive interaction between the adjacent bonds. Such a type of repulsive interaction is called torsional strain.'

The NCERT text defines this: 'One such conformation in which hydrogen atoms attached to two carbons are as closed together as possible is called eclipsed conformation and the other in which hydrogens are as far apart as possible is known as the staggered conformation.'

The NCERT text explicitly states, 'It may be remembered that in all the conformations, the bond angles and the bond lengths remain the same.'

The NCERT text describes Newman projections: 'In this projection, the molecule is viewed at the C–C bond head on. The carbon atom nearer to the eye is represented by a point... The rear carbon atom... is represented by a circle...'

The NCERT text describes Sawhorse projections: 'In this projection, the molecule is viewed along the molecular axis. It is then projected on paper by drawing the central C–C bond as a somewhat longer straight line. Upper end of the line is slightly tilted towards right or left hand side.'

The NCERT text states, 'Such spatial arrangements of atoms which can be converted into one another by rotation around a C-C single bond are called conformations or conformers or rotamers.'

The NCERT text mentions, 'It is hindered by a small energy barrier of 1-20 kJ mol$^{-1}$ due to weak repulsive interaction between the adjacent bonds.'

The NCERT text states, 'Any other intermediate conformation is called a skew conformation.'

The summary section of the NCERT text clearly states, 'Alkanes show conformational isomerism due to free rotation along the C–C sigma bonds.'

The NCERT text explains, 'Three hydrogen atoms attached to the front carbon atom are shown by three lines drawn at an angle of 120° to each other.'