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
- Both Statement I and Statement II are false
- Statement I is true but Statement II is false
- Both Statement I and Statement II are true
Answer
(4) Both Statement I and Statement II are true
Solution
Statement I: b.p. (K): HCl 189, HBr 206, HI 238, HF 293.
From HCl to HI, b.p. rises with size (stronger van der Waals forces); HF has the highest b.p. due to strong H-bonding.
HCl < HBr < HI < HF true.
Statement II: m.p. (K): HCl 159, HBr 186, HF 190, HI 222.
HCl < HBr < HF < HI true.
(As per NCERT, Table 7.8: the m.p. of HF lies between those of HBr and HI.)
Answer: (4)