Diborane

Q.

${\mathrm{SbF}}_5$ reacts with ${\mathrm{XeF}}_4$ to form an adduct. The shapes of cation and anion in the adduct are respectively:

1. Square planar, trigonal bipyramidal

2. Square planar, octahedral

3. T-shaped, octahedral

4. Square pyramidal, octahedral

Q. $1)$ How will you carry out the following conversion?


$2)$ How will you carry out the following conversion?

Q. The product obtained in the reaction of diborane with excess of ammonia at low temperature is:

1. $3B_2{H}_6\cdot 2N{H}_3$
2. $(BN{)}_2$
3. $B_3{N}_3{H}_6$
4. $(BN{)}_4$

Q. In the given reaction, $B_2{H}_6+2KOH+2X\to 2Y+6H_2,$ X and Y are respectively

1. $H_2,H_{3}B{O}_3$
2. $HCl,KB{O}_3$
3. $H_{2}O,KB{O}_3$
4. $H_{2}O,KB{O}_2$

Q. Which of the following statements is incorrect regarding diborane?

1. It has only two bridging hydrogens
2. When methylated, the product formed is $M{e}_4{B}_2{H}_2$
3. The bridging hydrogen atoms are in a plane perpendicular to the other ones
4. All the B-H bonds are of equal lengths

Q. Borohydrides are prepared by reaction of metal hydrides with $B_2{H}_6$ in diethyl ether, select incorrect statement:

1. Hybridisation of Boron changes
2. Metal $M$ can be $LiorNa$
3. Geometry around boron is tetrahedral in both reactant and product
4. Boron hydrides are used as reducing agent

Q.

Which one of the following statements is not true regarding diborane?

1. It has two bridging hydrogenes and four perpendicular to the rest

2. When methylated, the product is $M{e}_4{B}_2{H}_2$

3. The bridging hydrogenes are in a plane perpendicular to the rest.

4. All the B-H bond distances are equal.

Q. Diborane reacts with carbon monoxide forming :

1. an oxidising product $B_2{O}_3$
2. a adduct $2B{H}_3.CO$
3. an oxidising product $2B{H}_3.CO$
4. an oxidising product $B{H}_3$

Q. Incorrect statement regarding X in the given reaction is: $B{F}_3+LiAl{H}_4\to \left(X\right)+LiF+Al{F}_3$

1. 12 electrons are involved in bonding
2. It has four (2 centre-2 electron) bonds
3. It has two (three centre-two electron) bonds
4. X does not react with ammonia

Q. The structure of diborane contains:

1. four $2C-2e$ bonds and two $3C-2e$ bonds
2. two $2C-2e$ bonds and four $3C-2e$ bonds
3. two $2C-2e$ bonds and two $3C-2e$ bonds
4. four $2C-2e$ bonds and four $3C-2e$ bonds

Q. Which of the following statement is correct for diborane?

1. Small amines like $N{H}_3,C{H}_{3}N{H}_2$ give unsymmetrical cleavage of diborane
2. Large amines such as $(C{H}_3{)}_{3}N$ and pyriding gives symmetrical cleavage of diborane
3. Small as well as large amines both gives symmetrical cleavage of diborane
4. (A) and (B) both

Q.

Diborane

1. is electron deficient

2. burns spontaneously in air

3. has 3c-2e bonds

4. all of the above

Q. A metal $M$ reacts with sodium hydroxide to give a white precipitate $X$ which is soluble in excess of $NaOH$ to give $Y$. Compound $X$ is soluble in $HCl$ to form a compound $Z$. Identify $M,X,Y$ and $Z$.

1. $Si-M,$ $Si{O}_2-X$, $N{a}_{2}Si{O}_3-Y$, $SiC{l}_4-Z$
2. $Al-M,$ $Al(OH{)}_3-X$, $NaAl{O}_2-Y$, $AlC{l}_3-Z$
3. $Mg-M,$ $Mg(OH{)}_3-X$, $NaMg{O}_3-Y$, $MgC{l}_2-Z$
4. $Ca-M,$ $Ca(OH{)}_2-X$, $N{a}_{2}C{O}_3-Y$, $NaHC{O}_3-Z$

Q. If in diborane, the bond angle of H(bridged)-B-H(bridged) is ${97}^{\circ }$, then the bond angle of B-H(bridged)-B (in degree) would be

Q. A compound of boron X reacts at ${200}^{\circ }C$ temperature with $N{H}_3$ to give another compound $Y$ which is called as inorganic benzene. The compound $Y$ is a colourless liquid and is highly sensitive. Its melting point is $-{57}^{\circ }C$. The compound $X$ with excess $N{H}_3$ and at a still higher temperature gives boron nitride ${\left(BN\right)}_n$. The compounds $X$ and $Y$ respectively are:

1. $B{H}_3\text{and}{B}_2{H}_6$
2. $NaB{H}_4\text{and}{C}_6{H}_6$
3. $B_2{H}_6\text{and}{B}_3{N}_3{H}_6$
4. $B_4{C}_3\text{and}{C}_6{H}_6$

Q.

$LiH+B_2{H}_6\stackrel{Ether}{\to }A.$ A is as follows

1. $LiBH$

2. $LiB{H}_2$

3. $LiB{H}_4$

4. $\text{None of these}$

Q.

$B_2{H}_6.2N{H}_3\underset{{200}^{\circ }C}{\overset{\Delta }{\to }}A+H_2$. A is as follows

1. $B_3{N}_3{H}_6$

2. $B_2{N}_2{H}_6$

3. $B_4{N}_4{H}_6$

4. $\text{None of these}$

Q. Diborane is a :
1. Colourless gas
2. Coloured gas
3. Toxic gas
4. Non-toxic gas

1. 1, 2
2. 1, 3
3. 1, 2, 3
4. 2, 4

Q. Which of the following are reducing agents?

1. Diborane
2. $LiB{H}_4$
3. $LiAl{H}_4$
4. $NaB{H}_{3}CN$

Q. Number of sigma bonds present in borazine is same as :

1. Toluene
2. Benzene
3. Aniline
4. Phenol

Q. The total number of atoms lie in a same plane in diborane are :

1. 4
2. 6
3. 8
4. 2

Q.

In which of the following, a salt of type $KM{O}_2$ (M = Al or B) is obtained?

1. 

2. 

3. 

4. 

Q. In the given reaction, $B_2{H}_6+2KOH+2X\to 2Y+6H_2,$ X and Y are respectively

1. $H_2,H_{3}B{O}_3$
2. $HCl,KB{O}_3$
3. $H_{2}O,KB{O}_3$
4. $H_{2}O,KB{O}_2$

Q. By which of the following reactions borazine is prepared?

1. $B_2{H}_6+N{H}_3\left(\text{excess}\right)\stackrel{\text{low temperature}}{\to }$
2. $B_2{H}_6+N{H}_3\left(\text{excess}\right)\underset{\text{Higher temperature}(>{200}^{o}C)}{\overset{\text{high temperature}}{\to }}$
3. $B_2{H}_6+N{H}_3\underset{ratio2N{H}_3:1B_2{H}_6}{\overset{\text{high temperature}\left({200}^{o}C\right)}{\to }}$
4. None of these

Q. Incorrect statement regarding X in the given reaction is: $B{F}_3+LiAl{H}_4\to \left(X\right)+LiF+Al{F}_3$

1. 12 electrons are involved in bonding
2. It has four (2 centre-2 electron) bonds
3. It has two (three centre-two electron) bonds
4. X does not react with ammonia

Q.

An alkene ‘A’ contains three C – C, eight C – H σ bonds and one C – C π bond. ‘A’ on ozonolysis gives two moles of an aldehyde of molar mass 44 u. Write IUPAC name of ‘A’.

Q. $B_2{H}_6+Na\to X+Y$
$B_2{H}_6+NaB{H}_4\to Y+Z$
Identify X, Y and Z.

1. $X=Na{B}_3{H}_8,Y=NaB{H}_4,Z=H_2$
2. $X=NaB{H}_4,Y=Na{B}_3{H}_4,Z=H_2$
3. $X=Na{B}_3{H}_4,Y=NaB{H}_4,Z=H_2$
4. $X=NaB{H}_4,Y=Na{B}_3{H}_8,Z=H_2$

Q. What are the products formed when diborane reacts with each of the following compounds?

1. $B_2{O}_3$
2. $H_{3}B{O}_3$
3. $KB{O}_2$
4. $BC{l}_3$

Q. From $B_2{H}_6$, the following can be prepared, except for:

1. $H_{3}B{O}_3$
2. $B_2(C{H}_3{)}_4{H}_2$
3. $B_2(C{H}_3{)}_6$
4. $NaB{H}_4$

Q. The structure of diborane $\left(B_2{H}_6\right)$ contains

1. Four $2c-2e^{-}$ bonds and four $3c-2e^{-}$ bonds
2. Four $2c-2e^{-}$ bonds and two $3c-2e^{-}$ bond
3. Two $2c-2e^{-}$ bonds and two $3c-3e^{-}$ bond
4. Two $2c-2e^{-}$ bonds and four $3c-2e^{-}$ bonds