Orthoboric Acid

Q.

Explain why ${\mathrm{BF}}_3$ behaves as a lewis acid.

Q. On addition of catechol to aqueous solution of boric acid, it will :

1. increase the pH of solution
2. decrease the pH of the solution
3. form polymeric metaborate species
4. leave the solution undisturbed.

Q. Which is true in case of boric acid $\left(H_{3}B{O}_3\right)$ ?

1. It is a white crystalline solid
2. It is sparingly soluble in water
3. It is highly soluble in hot water
4. All of the above.

Q.

$H_{3}B{O}_3$ is

1. Monobasic and weak Brosted acid

2. Tribasic and weak Bronsted acid

3. Monobasic and weak Lewis acid

4. Monobasic and strong Lewis acid

Q. When orthoboric acid $\left(H_{3}B{O}_3\right)$ is heated, the residue is:

1. Boric anhydride
2. Borax
3. Boron
4. Diborane

Q.

Orthoboric acid when heated to red hot gives

1. Metaboric acid

2. Metaboric acid

3. Boron and water

4. Boric anhydride

Q. Orthoboric acid is a acid.

1. monobasic
2. dibasic
3. tribasic

Q. Identify the incorrect statement about orthoboric acid:

1. It has a layer structure in which planar $H_{3}B{O}_3$ units are connected by hydrogen bonds
2. $H_{3}B{O}_3$ is a weak monobasic Lewis acid
3. On heating orthoboric acid, it forms metaboric acid and when heated further until it is red hot, boric oxide is formed
4. A mixture of ethyl alcohol with boric acid burns with a blue edged flame due to the formation of volatile ethyl borate

Q. Boric acid is polymeric due to

1. it acidic nature
2. the presence of hydrogen bonds
3. it monobasic nature
4. it geometry

Q.

$B(OH{)}_3+NaOH\rightleftharpoons NaB{O}_2+Na[B(OH{)}_4{]}^{-}+H_{2}O$

How can the reaction above be made to proceed in the forward reaction?

1. Addition of borax

2. Addition of cis-1, 2-diol

3. Addition of $N{a}_{2}HP{O}_4$

4. Addition of trans-1, 2-diol

Q. Boric acid is an acid because its molecule

1. Accepts $O{H}^{-}$ from water releasing proton
2. Combines with proton from water molecule
3. Contains replaceable $H^{+}$ ion
4. Gives up a proton

Q. Orthoboric acid is a acid.

1. monobasic
2. dibasic
3. tribasic

Q. Boric acid is an acid because its molecule

1. Contains replaceable $H^{-}$ ions

2. Gives up protons

3. Accepts $O{H}^{-}$ from water releasing a proton

4. Combines with a proton from water molecules

Q. On heating, orthoboric acid gives metaboric acid along with .

1. oxygen
2. hydrogen
3. water

Q.

When strongly heated, orthoboric acid leaves a residue of:

1. Metaboric acid

2. Tetraboric acid

3. Boric anhydride

4. Boron

Q. Boric acid is prepared from borax by the action of

1. HCl
2. NaOH
3. $C{O}_2$
4. $N{a}_{2}C{O}_3$

Q.

The correct statement(s) for orthoboric acid is(are)

1. It behaves as a weak acid in water due to self ionization

2. Acidity of its aqueous solution increases upon addition of ethylene glycol

3. It has a three-dimensional structure due to hydrogen bonding

4. It is a weak electrolyte

Q. On addition of catechol to aqueous solution of boric acid, it will :

1. increase the pH of solution
2. decrease the pH of the solution
3. leave the solution undisturbed.
4. form polymeric metaborate species

Q.

$H_{3}B{O}_3$ is

1. Monobasic and weak Brosted acid

2. Monobasic and weak Lewis acid

3. Monobasic and strong Lewis acid

4. Tribasic and weak Bronsted acid

Q. Pure orthoboric acid exists as a .

1. solid
2. liquid
3. gas

Q. On heating, orthoboric acid gives metaboric acid along with .

1. oxygen
2. hydrogen
3. water

Q. A mixture of boric acid with ethyl alcohol burns with a green flame due to the formation of:

1. Ethyl borax
2. Ethyl borate
3. Methyl borax
4. Methyl borate

Q. When orthoboric acid $\left(H_{3}B{O}_3\right)$ is heated, the residue is:

1. Boron
2. Diborane
3. Boric anhydride
4. Borax

Q. Which of the following statement (s) about $H_{3}B{O}_3$ is / are correct?

1. It is a strong tribasic acid.
2. It is prepared by acidifying an aqueous solution of borax
3. It has a layer structure in which planar $B{O}_3$ units are joined by hydrogen bonds.
4. It does not act as proton donor as it acts as a lewis acid by accepting lone pair hydroxyl ions.

Q.

Read the following and select one the correct answer.

Statement I: In water, orthoboric acid behaves as a weak monobasic acid

Statement II: In water, orthoboric acid acts as a proton donor

1. Statement I and Statement II are both correct. Statement II correctly explains Statement I

2. Statement I and Statement II are both correct. Statement II does not explain Statement I

3. Statement II is correct and Statement I is wrong

4. Statement I is correct and Statement II is wrong