The structure of diborane (B2H6) contains:
| 1. | four 2C-2e- bonds and four 3C-2e- bonds |
| 2. | two 2C-2e- bonds and two 3C-3e- bonds |
| 3. | two 2C-2e- bonds and four 3C-2e- bonds |
| 4. | four 2C-2e- bonds and two 3C-2e- bonds |
Aluminium chloride exists as dinner, Al2Cl6 in the solid state as well as in the solution of non-polar solvents such as benzene. When dissolved in acidified aqueous solution, it gives:
1. \(\mathrm{Al}^{3+}+3 \mathrm{Cl}^{-}\)
2. \(\left[\mathrm{Al}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}+3 \mathrm{Cl}^{-} \)
3. \(\left[\mathrm{Al}(\mathrm{OH})_{6}\right]^{3-}+3 \mathrm{HCl}\)
4. \(\mathrm{Al}_{2} \mathrm{O}_{3}+6 \mathrm{HCl}\)
In the structure of silicon dioxide:
| 1. | There are double bonds between silicon and oxygen atoms. |
| 2. | Silicon atom is bonded to two oxygen atoms. |
| 3. | Each silicon atom is surrounded by two oxygen atoms and each oxygen atom is bonded to two silicon atoms. |
| 4. | Each silicon atom is surrounded by four oxygen atoms and each oxygen atom is bonded to two silicon atoms. |
Graphite is a soft solid lubricant extremely difficult to melt. The reason for this anomalous behavior is that graphite :
| 1. | is a non-crystalline substance. |
| 2. | is an allotropic form of diamond. |
| 3. | has molecules of variable molecular masses like polymers. |
| 4. | has carbon atoms arranged in large plates of rings of strongly bound carbon atoms with weak interplate bonds. |
The bond dissociation energy of B – F in BF3 is 646 kJ mol–1 , whereas that of C – F in CF4 is 515 kJ mol–1. The correct reason for the higher B-F bond dissociation energy as compared to that of C-F is :
1. Smaller size of B-atom as compared to that of C-atom
2. Stronger σ bond between B and F in BF3 as compared to that between C and F in CF4
3. Significant pπ − pπ interaction between B and F in BF3 whereas there is no possibility of such interaction between C and F in CF4
4. Lower degree of pπ − pπ interaction between B and F in BF3 than that between C and F in CF4
In view of the signs of for the following reactions:
The oxidation states more characteristic for lead and tin are respectively:
1. For lead +2, for tin +2
2. For lead +4, for tin +4
3. For lead +2, for tin +4
4. For lead +4, for tin +2
Which one of the following boron anions cannot be formed?
1. BF63−
2. BH4−
3. B(OH)4−
4. BO33-
Which among the following halides is inert towards hydrolysis?
1. BF3
2. SiCl4
3. PCl5
4. SF6
The correct statement about B2H6 is:
| 1. | The terminal B–H bonds have less p-character when compared to bridging bonds. |
| 2. | The two B–H–B bonds are not of the same length. |
| 3. | All B–H–B angles are 120°. |
| 4. | Its fragment, BH3, behaves as a Lewis base. |
Given below are two statements:
| Statement I: | Colourless cupric metaborate is reduced to cuprous metaborate in a luminous flame. |
| Statement II: | Cuprous metaborate is obtained by heating boric anhydride and copper sulphate in a non-luminous flame. |
In the light of the above statements, choose the most appropriate answer from the options given
below.
1. Statement I is true but Statement II is false
2. Both Statement I and Statement II are false
3. Statement I is false but Statement II is true
4. Both Statement I and Statement II are true