NCERT Exemplar Class 11 Chemistry Chapter 12 MCQ

(c) The compound is certainly mesoExplanation:Meso compound does not rotate plane polarised light. Compound which contains tetrahedral atoms with four different groups but the whole molecule is a chiral, is known as meso compound. It possesses a plane of symmetry and is optically inactive. One of the asymmetric carbon atoms turns the plane of polarised light to the right and other to the left and to the same extent so that the rotation due to upper half is compensated by the lower half, i.e., internally compensated, and finally there is no rotation of plane polarised light.

(c) HalogenExplanation:Halogen element is estimated by Carius method

(a) displacement of σ electronsExplanation:During inductive effect shifting of a electrons takes place due to which partially charges are developed on the atom.+δ” +δ′ +δ −δC− C− C −Cl−

(c) Perfect geometric patternExplanation:A crystalline solid is one which possesses perfect geometry, high stability, symmetric and regularly arranged.

(a) CH3C ≡ NExplanation:Due to the presence of a lone pair of electrons on N, CH3C ≡ N: acts as a nucleophile. Further due to greater electronegativity of N than C, the C atom of −C ≡ N carries a positive charge and hence behaves as an electrophile.