Chemistry>Inorganic Chemistry>The p-Block Elements>Some Important Compounds of Boron

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Boric acid is used in carom boards for smooth gliding of pawns because

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Important Questions on The p-Block Elements

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Chemistry>Inorganic Chemistry>The p-Block Elements>Some Important Compounds of Boron

The green colour produced in the borax bead test of a chromium(III) salt is due to -

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Chemistry>Inorganic Chemistry>The p-Block Elements>Some Important Compounds of Boron

Hydrolysis of

B C l_{3}

gives X which on treatment with sodium carbonate produces

Y, X

and

Y

respectively, are

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Chemistry>Inorganic Chemistry>The p-Block Elements>Some Important Compounds of Boron

Diborane

(B_{2} H_{6})

reacts independently with

O_{2}

and

H_{2} O

to produce, respectively:

EASY

Chemistry>Inorganic Chemistry>The p-Block Elements>Some Important Compounds of Boron

A mixture of Boron trichloride and hydrogen is subjected to silent electric discharge to form

x

and

HCl

.

x

is mixed with

{NH}_{3}

and heated to

200^{0} C

to form

y

. The formula of

y

is

EASY

Chemistry>Inorganic Chemistry>The p-Block Elements>Some Important Compounds of Boron

{AlF}_{3}

is soluble in

HF

only in presence of

KF

. It is due to the formation of

HARD

Chemistry>Inorganic Chemistry>The p-Block Elements>Some Important Compounds of Boron

Choose the correct statements about diborane;
I. It is prepared by the oxidation of sodium borohydride with iodine.
II. It undergoes cleavage reactions with Lewis bases to give borane adducts.
III. It is produced on an industrial scale by the reaction of

{BF}_{3}

with

{LiAlH}_{4}

.
IV. It is readily hydrolysed by water to give borazine.
V. It burns in oxygen and gives boron trioxide.

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Chemistry>Inorganic Chemistry>The p-Block Elements>Some Important Compounds of Boron

The Lewis acid strength of

B B r_{3}, B C l_{3}

and

B F_{3}

is in the order

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Chemistry>Inorganic Chemistry>The p-Block Elements>Some Important Compounds of Boron

Which of the following represents the structure of inorganic benzene?

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Chemistry>Inorganic Chemistry>The p-Block Elements>Some Important Compounds of Boron

A l_{2} {(S O_{4})}_{3}

is used for a variety of purposes but not

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Chemistry>Inorganic Chemistry>The p-Block Elements>Some Important Compounds of Boron

A l_{2} O_{3}

reacts with

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Chemistry>Inorganic Chemistry>The p-Block Elements>Some Important Compounds of Boron

When aqueous solutions of borax is acidified with

HCl

, we get

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Chemistry>Inorganic Chemistry>The p-Block Elements>Some Important Compounds of Boron

When a mixture of diborane and ammonia is heated, the final product is

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Chemistry>Inorganic Chemistry>The p-Block Elements>Some Important Compounds of Boron

The order of acidic strength of boron trihalides

HARD

Chemistry>Inorganic Chemistry>The p-Block Elements>Some Important Compounds of Boron

The reaction of

H_{3} N_{3} B_{3} C l_{3} (A)

with

L i B H_{4}

in tetrahydrofuran gives inorganic benzene

(B)

. Further, the reaction of

(A)

with

(C)

leads to

H_{3} N_{3} B_{3} {(M e)}_{3}

. Compounds

(B)

and

(C)

respectively, are:

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Chemistry>Inorganic Chemistry>The p-Block Elements>Some Important Compounds of Boron

In diborane ____ are present.

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Chemistry>Inorganic Chemistry>The p-Block Elements>Some Important Compounds of Boron

A Lewis acid

' X'

reacts with

{LiAlH}_{4}

in ether medium to give a highly toxic gas. This gas when heated with

{NH}_{3}

gives a compound commonly known as inorganic benzene. The gas is

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Chemistry>Inorganic Chemistry>The p-Block Elements>Some Important Compounds of Boron

H_{3} {BO}_{3}

is

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Chemistry>Inorganic Chemistry>The p-Block Elements>Some Important Compounds of Boron

In the structure of borax, the numbers of boron atoms and B - O - B units, respectively, are

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Chemistry>Inorganic Chemistry>The p-Block Elements>Some Important Compounds of Boron

Boric acid is an acid because its molecule

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Chemistry>Inorganic Chemistry>The p-Block Elements>Some Important Compounds of Boron

The number of

2

-centre-

2

-electron and

3

-centre-

2

-electron bonds in

B_{2} H_{6}

, respectively, are: