JEE MainChemistryp Block Elements (Group 13 & 14)
Given below are four statements: (A) SnO and PbO are amphoteric and dissolve in excess NaOH to form soluble hydroxo complexes. (B) CO is a neutral oxide, whereas GeO is distinctly acidic. (C) During the formation of the BF ₃ NH ₃ adduct, the B - F bond length decreases. (D) The geometry around Boron changes from trigonal planar to tetrahedral upon adduct formation. Choose the most appropriate answer from the options
Options
- A(A), (B), (C) and (D)
- B(A), (C) and (D) only
- C(A), (B) and (D) only
- D(B), (C) and (D) only
Correct answer
C. (A), (B) and (D) only
Step-by-step solution
Statement (A) is true. Both SnO and PbO are amphoteric and react with strong bases like NaOH to form soluble stannite and plumbite complexes, respectively. Statement (B) is true. Among the monoxides of Group 14, CO is neutral, GeO is distinctly acidic, while SnO and PbO are amphoteric. Statement (C) is false. In free BF ₃ , the B - F bonds have partial double bond character due to p -p back-bonding. When the adduct BF ₃ NH ₃ is formed, the vacant 2p orbital of boron accepts a lone pair from nitrogen, destroying the