Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :
- Statement I is false but Statement II is true
- Statement I is true but Statement II is false
- Both Statement I and Statement II are false
- Both Statement I and Statement II are true
Answer
(2) Statement I is true but Statement II is false
Solution
Statement I: Electronegativity decreases down group 15: N (3.0) > P (2.1) > As (2.0) > Sb (1.9)
X = N (most), Y = Sb (least).
As per NCERT, N2O3 and P2O3 are acidic, As2O3 and Sb2O3 are amphoteric and Bi2O3 is basic.
X2O3 (N2O3) is acidic and Y2O3 (Sb2O3) is amphoteric. Statement I is true.
Statement II: BCl3 is covalent and is hydrolysed:
BCl3 + 3H2O B(OH)3 + 3HCl
B(OH)3 + 2H2O [B(OH)4]- + H3O+
B has no d orbitals, its maximum covalency is 4 [B(H2O)6]3+ cannot form (it is Al that gives [Al(H2O)6]3+ in water). Statement II is false.
Answer: (2)