Which statement is not correct about the trends in properties of the hydrogen halides from HCl to HI ?
A The boiling points decrease - AQA - A-Level Chemistry - Question 17 - 2019 - Paper 3
Question 17
Which statement is not correct about the trends in properties of the hydrogen halides from HCl to HI ?
A The boiling points decrease.
B The bond dissociation energy... show full transcript
Worked Solution & Example Answer:Which statement is not correct about the trends in properties of the hydrogen halides from HCl to HI ?
A The boiling points decrease - AQA - A-Level Chemistry - Question 17 - 2019 - Paper 3
Step 1
A The boiling points decrease.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
This statement is incorrect. The boiling points of hydrogen halides actually increase from HCl to HI due to the increasing strength of van der Waals forces as the size of the halogen increases.
Step 2
B The bond dissociation energy of H−X bond decreases.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
This statement is correct. The bond dissociation energy does decrease from HCl to HI due to the weakening of the H−X bond as the size of the halogen increases.
Step 3
C The polarity of the H−X bond decreases.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
This statement is correct. The polarity of the H−X bond decreases from HCl to HI because the electronegativity difference between hydrogen and the halogens decreases from chlorine to iodine.
Step 4
D They are more easily oxidised in aqueous solutions.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
This statement is correct. The hydrogen halides become more easily oxidised in aqueous solutions due to the larger size and lower electronegativity of iodine compared to chlorine.
