Which one of the following anions is present in chain structure silicates?
(a) Si2O6-7 (b) (Si2O2-5)n
(c) (Si2O4-6)n (d) SiO4-4
BX3+NH3R.T.→BX3 .NH3+ Heat of adduct formation (∆H)
The numerical value of ∆H is found to be maximum for :
(1) BF3
(2) BCl3
(3) BBr3
(4) BI3
Borax is converted into crystalline boron by the following steps:
BoraxX→H3BO3∆→B2O3Y→∆B
X and Y are respectively :
1. HCl, Mg
2. HCl, C
3. C, Al
4. HCl, Al
The dissolution of Al(OH)3 in a solution of NaOH results in the formation of -
1. [Al(H2O)4(OH)2]+
2. [Al(H2O)3(OH)3]
3. [Al(H2O)2(OH)4]-
4. [Al(H2O)6(OH)3]
Choose the correct squence for the geometry of thr given molecules Borazone, Borazole, B3O3-6, Fe2Cl6, trimer of FCN. ('P' stands for planar and 'NP' stdans for non-planar)
(1) NP, NP, NP, P, P
(2) P, P, NP, NP, P
(3) NP, NP, NP, P, NP
(4) NP, P, P, NP, P
Which of the following oxidation states are the most characteristics for lead and tin respectively?
1. +4, +2
2. +2, +4
3. +4, +4
4. +2, +2
Name the type of the structure of silicate in which one oxygen atom of [SiO4]4- is
shared?
1. Sheet silicate
2. Pyrosilicate
3. three dimensional silicate
4. Linear chain silicate
The number of carbon atoms per unit cell of diamond unit cell is:-
1. 4
2. 8
3. 6
4. 1
The incorrect statement among the following regarding borax is-
1. It is a useful primary standard for titrating against acids.
2. One molecule of borax contains 4 B — O — B bonds.
3. Aqueous solution of borax can be used as a buffer.
4. It is made up of two triangular BO_{3} units and two tetrahedral BO_{4} units.
It is because inability of ns2 electrons of the valence shell to participate in bonding that
1. Sn2+ is reducing while Pb4+ is oxidising agent
2. Sn2+ is oxidising while Pb4+ is reducing agent
3. Sn2+ and Pb2+ are both oxidising and reducing agent
4. Sn4+ is reducing while Pb4+ is oxidising agent