Advertisements
Advertisements
Question
Describe the general trends in the following properties of the elements in Groups 13 and 14.
Nature of halides
Advertisements
Solution
Except thallium, All the elements of the boron family combine with three atoms of halogens to form trihalides. All these halides exist as molecular species with hybridisation of sp2. All the trihalides are Lewis acid and their acidic strength of trihalides of boron is in order: Bf3 < BCl3 < BBr3 < Bl3. In group-14, except carbon, all group 14 elements on reaction with halogens form tetra halides where central metal atom shows the sp3 hybridisation state and corresponding tetrahedral shape.
There are few exceptions also, SnF4 and Pf4 are ionic in nature, while the rest are covalent compounds.
APPEARS IN
RELATED QUESTIONS
How can you explain higher stability of BCl3 as compared to TlCl3?
Suggest reasons why the B–F bond lengths in BF3 (130 pm) and `"BF"_4^(-)` (143 pm) differ.
Aluminium trifluoride is insoluble in anhydrous HF but dissolves on the addition of NaF. Aluminium trifluoride precipitates out of the resulting solution when gaseous BF3 is bubbled through. Give reasons.
What happens when BF3 is reacted with ammonia?
In some of the reactions thallium resembles aluminium, whereas in others it resembles with group I metals. Support this statement by giving some evidences.
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.
Aluminium dissolves in mineral acids and aqueous alkalies and thus shows amphoteric character. A piece of aluminium foil is treated with dilute hydrochloric acid or dilute sodium hydroxide solution in a test tube and on bringing a burning matchstick near the mouth of the test tube, a pop sound indicates the evolution of hydrogen gas. The same activity when performed with concentrated nitric acid, reaction doesn’t proceed. Explain the reason.
Explain the following:
PbX2 is more stable than PbX4.
Explain the following:
Electron gain enthalpy of chlorine is more negative as compared to fluorine.
Explain the following:
Tl (NO3)3 acts as an oxidising agent.
Identify the compounds A, X and Z in the following reactions:
\[\ce{A + 2HCl + 5H2O -> 2NaCl + X}\]
Complete the following chemical equations:
\[\ce{Z + 3 LiAlH4 -> X + 3LiF + 3AlF_3}\]
\[\ce{X + 6H2 -> Y + 6H2}\]
\[\ce{3X + 3O2 ->[Δ] B2O3 + 3H2O}\]
Match the species given in Column I with properties given in Column II.
| Column I | Column II |
| (i) Diborane | (a) Used as a flux for soldering metals |
| (ii) Galluim | (b) Crystalline form of silica |
| (iii) Borax | (c) Banana bonds |
| (iv) Aluminosilicate | (d) Low melting, high boiling, useful for measuring high temperatures |
| (v) Quartz | (e) Used as catalyst in petrochemical industries |
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.
Ionisation enthalpy
Account for the following observations:
Though fluorine is more electronegative than chlorine yet BF3 is a weaker Lewis acid than BCl3
Which one of the following is the correct statement?
