MCQs MDCAT 4-A ,F.Sc-I CH#6....Answer Key with Explanation

• Q.1 The nu2
• ber of sigma bonds ratio to pi-bonds in Toluene is

           A) 15 : 3
           B) 15 : 0
           C) 15 : 1
           D) 14 : 0

• Q.2 Which of the following is iso-structural with Carbonate ion

           A) PH3
           B) lF3
           C) SO3
           D) NH3

• Q.3 All types of chemical bonds are present in

            A) KOH
            B) H2O
            C) NH4OH
            D) [Co(H2O)6]

• Q.4   The dative bond is formed according to Valence bond theory between 

           A) Half-filled orbitals
           B) Empty orbitals
           C) Empty and full-filled orbitals
           D) Full-filled orbitals

• Q.5  The incorrect 1st ionization energy order is

           A) S > P
           B) Be > B
           C) He > F
           D) N > O  




          Answers :
          Q.1 = B             Q.2 = C             Q.3 = C                      Q.4 = C              Q.5 = A
          Explanation:
          Q.1  In toluene or methylbenzene there are six bonds present between C-C in the ring,one C-C bond between ring carbon and methly carbon,five C-H bonds with ring and three C-H sigma bonds in methyl group but there are delocalized pi-electronic cloud is present in the ring so no true pi-bonds are present in the ring according to modern orbital treatment structure of benzene. So 15 sigma binds and 0 pi-bonds.
        Q.2  The structure of carbonate ion resemble with SO3.Both follow AB3 pattern according to VSEPR theory.Following are structures of all compounds in options.

Q.3