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The order of acidic strenght boron triha...

The order of acidic strenght boron trihalides is:

A

`BF_(3) lt BCl_(3) lt B B r_(3) lt B_(3)`

B

`B_(3) lt B Br_(3) lt BCl_(3) lt BF_(3)`

C

`B Br_(3) lt BCl_(3) lt BF_(3) lt B_(3)`

D

`BF_(3) lt B_(3) lt BCl_(3) lt B Br_(3)`

Text Solution

Verified by Experts

The correct Answer is:
A
Boron trihalides are Lewis acid the order of their acidic strength is as follows
`BF_(3) lt BCl_(3) lt B Br_(3) lt Bl_(3)`
The `p pi- p pi` back bonding has maximum effect in `BF_(3)` as the size of B and F-atoms are comparable and this effect decreases as the size of halogen increases. due to this effect, tendency of accepting lone pair of electron of boron decreases i.e., lewis acid character decreases.
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Boron, the first member of group 13 (p-block) is a typical non-metal. H exists in two allotropic forms. The compounds of boron are mainly electron deficient as well as Lewis acids. For example, all the trihalides of boron (BX_(3)) are Lewis acids. The expected order of acidic strength based on the electro negativity of halogen atoms is : BF_(3)gtBC l_(3)gtBBr_(3)gtBl_(3) . But the actual order is the reverse. This is explained with the help of the concept of back bonding (p pi- p pi) . Among the hydrides of boron. diborane has a bridged structure. Among the halides of the elements of group 13, the one which is most acidic is:

Boron, the first member of group 13 (p-block) is a typical non-metal. H exists in two allotropic forms. The compounds of boron are mainly electron deficient as well as Lewis acids. For example, all the trihalides of boron (BX_(3)) are Lewis acids. The expected order of acidic strength based on the electro negativity of halogen atoms is : BF_(3)gtBC l_(3)gtBBr_(3)gtBl_(3) . But the actual order is the reverse. This is explained with the help of the concept of back bonding (p pi- p pi) . Among the hydrides of boron. diborane has a bridged structure. Which of the following statements of group 13, the one which is most acidic is:

Boron, the first member of group 13 (p-block) is a typical non-metal. H exists in two allotropic forms. The compounds of boron are mainly electron deficient as well as Lewis acids. For example, all the trihalides of boron (BX_(3)) are Lewis acids. The expected order of acidic strength based on the electro negativity of halogen atoms is : BF_(3)gtBC l_(3)gtBBr_(3)gtBl_(3) . But the actual order is the reverse. This is explained with the help of the concept of back bonding (p pi- p pi) . Among the hydrides of boron. diborane has a bridged structure. In the reaction: BF_(3)+3LiBH_(4)rarr3liF+X is

The decreasing trend of acidic nature of trihalides of boron is:

The correct Lewis acid order for boron halides is

Knowledge Check

  • The order of acidic strength of boron trihalides

    A
    `BF_(3) lt BCl_(3) lt BBr_(3) lt BI_(3)`
    B
    `BI_(3) lt BBr_(3) lt BCl_(3) lt BF_(3)`
    C
    `BCl_(3) lt BBr_(3) lt BI_(3) lt BF_(3)`
    D
    `BBr_(3) lt BCl_(3) lt BF_(3) lt BI_(3)`

  • The unexpected order of acidic strength of the trihalides of boron can best be explained by.

    A
    `p pi-p pi` beack bonding
    B
    Hybridisation
    C
    Trigonal planar structure
    D
    None of the above

  • Boron forms BX_(3) type of halides. The correct increasing order of Lewis acid strength of these halides is

    A
    `BF_(3)gtBCl_(3)gtBBr_(3)gtBI_(3)`
    B
    `BI_(3)gtBBr_(3)gtBCl_(3)gtBF_(3)`
    C
    `BF_(3)gtBI_(3)gtBCl_(3)gtBBr_(3)`
    D
    `BF_(3)gtBCl_(3)gtBI_(3)gtBBr_(3)`
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