Chemical Properties of Boron Family

Q.

The oxidation state of Cr in $Cr{O}_6$ is

Q.

In ${\mathrm{P}}_4$ molecule phosphorus atoms are tetrahedrally arranged. The bond angle $\angle \mathrm{P}-\mathrm{P}-\mathrm{P}$ in the molecule is

Q.

Which species does not exist -

1. 

2. 

3. 

4. 

Q. 24. Which statements is/are incorrect ? (1) In alkali metals in a group, from top to bottom increase in size is maximum from Na to K (2) Addition of e in P atom will be exothermic (3) IP of F is greater than its EA value (4) Reaction O(g) + S(g) → O(g) + S(g) is endothermic

Q. what are strong bulky bases ? is NaNH2 AND liq. NH3 is bulky base

Q.

Answer the following:

1. Name the chief ore of aluminium.
2. Name the process used to concentrate the above mentioned ore.
3. Why is alumina added to cryolite in the electrolytic reduction of aluminium?
4. Give the cathode and anode reactions involved in extraction of aluminium from its above mentioned ore.
5. Name the process used for the concentration of zinc blende.
6. Name two ores from which Al is extracted by electrolysis.

Q. 9.Total number of degenerate orbitals in the second excited state of lithium 2+ ion is

Q. how to calculate oxidation number of CO3 ?

Q.

Give one word/a few words for each of the following.
Product of reaction of copper carbonate with dilute sulphuric acid.

Q. What is the oxidation state of Al in Al2Cl6. Explain with structure.

Q. All of the group 13 elements form ionic halides except

1. boron
2. thallium
3. gallium

Q.

Maximum covalent character is associated with the compound

1. Nal

2. Mgl₂

3. AlCl₃

4. All₃

Q. Oxidation number of Fe in Fe_{0.94}O is : (1)200 (2)200/94 (3)94/200 (4)None

Q. in which of the following dimer empty atomic orbital of central atom of monomer does not involve in hybridisation?(1)Ga2H6 (2)Al2Br6 (3)Be2H4 (4) Cl2O6

Q. (1) what is the Oxidation no. Of Co, Fe, Ni in [Co(NH3)6]3+, [Fe(CN)6]4- and [Ni(Co)4]?How? (2) Coordination no. Of [Fe(C2O4)3]3- and [Co(en)3]3+?How?

Q. Aluminium is usually found in its +3 oxidation state . In contrast, thallium exists in both +1 (more stable) and +3 (less stable) oxidation states. This is due to:

1. lanthanoid contraction
2. lattice effect
3. diagonal relationship
4. inert pair effect

Q. $BN+H_{2}O\to A+B.A\&B$ are as follows

1. $B_2{O}_3,N_2$
2. $B_2{O}_3,N{H}_3$
3. $H_{3}B{O}_3,N_2$
4. $H_{3}B{O}_3,N{H}_3$

Q. what is the stable oxidation state tin +2 or +4?

Q.

The correct structural representation of diborane is

1. [BH₂]⁺ + [BH₄]^-

2. 

3. 

4. 

Q. Which one of the following element shows amphoteric nature?

1. B
2. Al
3. both Al and B
4. Neither Al nor B

Q. 40. the diamagnetic ion is (1)Fe2+ (2)Sc2+ (3)Fe3+ (4)Zn2+ show the orbital diagram(by drawing orbitals as boxes)

Q. In acidic medium moles of KMnO4 required to oxidise 1.5 moles of Cu2S will be??

Q.

Which of the following mineral does not contain Al ?

1. Cryolite

2. Mica

3. Felspar

4. Fluorspar

Q. 37. Can oxidation number be expressed in fractions? If not what is the oxidation number of sulphur in sodium tetrathionate?

Q. what is oxidation state ? and what is the oxidation state of 1& 2 group?

Q.

Diamagnetic species can be

1. GaCl₂

2. All of these

3. B₂Cl₄

4. GaS

Q. SInce highest oxidation no of group 16 will be +6 and lowest will be -2 . but in case of H2O2 and O3 IT IS WRITTEN THAT OXYGEN HAS MAXIMUM oxidation state 0. WHY WHAT DOES THE DEFINITION OF OXIDATION STATE SAY ABOT THIS

Q. In which of the following dimer empty atomic orbitalof central atom of monomer does not involve in hybridisation?(1) Ga2H6 (2) Al2Br6, (3) Be2H4, (4) Cl2O

Q.

An aqueous solution of potash alum is -

1. Acidic

2. Alkaline

3. Neutral

4. None of these

Q.

The decrease stability of higher oxidation state in p-block with increasing atomic number is due to

1. Decrease in bond energy as going down the group

2. Energy required to unpair ${ns}^2$ electrons is not compensated by the energy released in forming the two additional bonds

3. Both (a) and (b) are correct

4. None of the above is correct