NTA Abhyas 2020
- Exam
- NTA Abhyas
- Year
- 2020
- Subject
- Chemistry
- Chapter
- p Block Elements (Group 13 & 14)
NTA Abhyas 2020 · Chemistry · p Block Elements (Group 13 & 14)
The correct Lewis acid order for boron halides is
The correct Lewis acid order for boron halides is
Options
- A{\text{BBr}_{3} \text{>}{\text{BCl}_{3} \text{>}{\text{Bl}_{3} \text{>}{\text{BF}_{3}
- B{\text{BI}_{3} \text{>}{\text{BF}_{3} \text{>}{\text{BBr}_{3} \text{>}{\text{BCl}_{3}
- C{\text{BF}_{3} \text{>}{\text{BCl}_{3} \text{>}{\text{BBr}_{3} \text{>}{\text{Bl}_{3}
- D{\text{BI}_{3} \text{>}{\text{BBr}_{3} \text{>}{\text{BCl}_{3} \text{>}{\text{BF}_{3}
Correct answer
D. {\text{BI}_{3} \text{>}{\text{BBr}_{3} \text{>}{\text{BCl}_{3} \text{>}{\text{BF}_{3}
Step-by-step solution
(i) On the basis of back bonding, smaller be the halide atom, more effective be the back bonding and show less tendency to accept pair of electrons
(ii) Size of halides increases down the group hence ability to accept pair of electrons increases down the group.
Hence, correct order of Lewis acid for boron-halides is
{\text{Bl}_{3} \text{>}{\text{BBr}_{3} \text{>}{\text{BCl}_{3} \text{>}{\text{BF}_{3}
(ii) Size of halides increases down the group hence ability to accept pair of electrons increases down the group.
Hence, correct order of Lewis acid for boron-halides is
{\text{Bl}_{3} \text{>}{\text{BBr}_{3} \text{>}{\text{BCl}_{3} \text{>}{\text{BF}_{3}