Advertisements
Advertisements
प्रश्न
A nonmetallic element of group 13, used in making bullet proof vests is extremely hard solid of black colour. It can exist in many allotropic forms and has unusually high melting point. Its trifluoride acts as Lewis acid towards ammonia. The element exihibits maximum covalency of four. Identify the element and write the reaction of its trifluoride with ammonia. Explain why does the trifluoride act as a Lewis acid.
Advertisements
उत्तर
Boron is the only non-metallic and extremely hard element in group 13, and it is also used to make bulletproof vests. Boron exists in a variety of allotropic forms. It usually has a high melting point and no d orbital.
Using 2s and 2p orbitals, it can achieve a maximum covalency of 4. Because the octet of boron is not completed in trivalent halides of boron, it acts as Lewis acid. It forms an adduct when it reacts with Lewis base.
\[\ce{BF3 + NH3 -> H3N - B - F3}\]
APPEARS IN
संबंधित प्रश्न
If B–Cl bond has a dipole moment, explain why BCl3 molecule has zero dipole moment.
Suggest reasons why the B–F bond lengths in BF3 (130 pm) and `"BF"_4^(-)` (143 pm) differ.
Write a balanced equation for Al + NaOH → ?
Write a balanced equation for B2H6 + NH3 → ?
The geometry of a complex species can be understood from the knowledge of type of hybridisation of orbitals of central atom. The hybridisation of orbitals of central atom in [Be(OH)4]– and the geometry of the complex are respectively.
Which of the following oxides is acidic in nature?
In the structure of diborane ______.
The most commonly used reducing agent is ______.
Cement, the important building material is a mixture of oxides of several elements. Besides calcium, iron and sulphur, oxides of elements of which of the group (s) are present in the mixture?
Explain why the following compounds behave as Lewis acids?
BCl3
Explain the following:
Boron does not exist as B3+ ion.
Explain the following:
Tl (NO3)3 acts as an oxidising agent.
Match the species given in Column I with the hybridisation given in Column II.
| Column I | Column II |
| (i) Boron in [B(OH)4]– | (a) sp2 |
| (ii) Aluminium in [Al(H2O)6]3+ | (b) sp3 |
| (iii) Boron in B2H6 | (c) sp3d2 |
| (iv) Carbon in Buckminsterfullerene | |
| (v) Silicon in \[\ce{SiO^{4-}4}\] | |
| (vi) Germanium in [GeCl6]2– |
Describe the general trends in the following properties of the elements in Groups 13 and 14.
Atomic size
Describe the general trends in the following properties of the elements in Groups 13 and 14.
Oxidation states
Describe the general trends in the following properties of the elements in Groups 13 and 14.
Nature of halides
Three pairs of compounds are given below. Identify that compound in each of the pairs which has group 13 element in more stable oxidation state. Give reason for your choice. State the nature of bonding also.
AlCl3 , AlCl
Boron compounds behave as Lewis acids because of their ______.
A group 13 element ‘X’ reacts with chlorine gas to produce a compound XCl3. XCl3 is electron deficient and easily reacts with NH3 to form \[\ce{Cl3X –> NH3}\] adduct; however, XCl3 does not dimerize X is ______.
