Question

In looking at the bolded atoms in the answer choices, which pair consists of molecules having the same geometry? hints in looking at the atoms in the answer choices, which pair consists of molecules having the same geometry? ch2o and ch3oh co2 and so2 ch2ccl2 and ch2ch2 pcl3 and bf3

Answer 1

Answer:

               1,1-Dichloroethene (CH₂CCl₂) and Ethene (H₂CCH₂) have same molecular geometries.

Explanation:

                      The molecular geometries of all molecules are drawn below. Among these molecules four molecules contains four atoms which has same geometry. These are Boron in BF₃, Carbon in CH₂O, both carbon atoms CH₂CCl₂ and both carbon atoms H₂CCH₂. All specified elements in these molecules have same geometry (Trigonal Planar). 

While, the overall geometry of only two molecules is same. Those two are CH₂CCl₂ and H₂CCH₂ because in these molecules all carbon atoms have Trigonal Planar Geometry. Hence, we can confirm that among given compounds this pair has same geometry.

Answer 2

Correct Answer: CH2CCI2 and CH2CH2.

Reason:
Structure of compound depends on the hybridization of central atom. In both of the above molecules (i.e. CH2CCL2 and CH2CH2). Central atom i.e. carbon is sp^2 hybridized.  Thus 3 hybridized orbitals of 'C' is involved in sigma bonding. Further, these orbitals are placed spatially at an angle of $120^{0}$. The un-hybridized 2pz orbital of 'C' is involved in pi-bonding. Due to this, both of the above molecules possess a triangular planner geometry.