Advertisements
Advertisements
प्रश्न
Suggest reasons why the B–F bond lengths in BF3 (130 pm) and `"BF"_4^(-)` (143 pm) differ.
Advertisements
उत्तर
The B–F bond length in BF3 is shorter than the B–F bond length `"BF"_4^(-)`. BF3 is an electron-deficient species. With a vacant p-orbital on boron, the fluorine and boron atoms undergo pπ – pπ back-bonding to remove this deficiency. This imparts a double-bond character to the B–F bond.
This double-bond character causes the bond length to shorten in BF3 (130 pm). However, when BF3 coordinates with the fluoride ion, a change in hybridisation from sp2 (in BF3) to sp3 (in `"BF"_4^(-)` ) occurs. Boron now forms 4σ bonds and the double-bond character is lost. This accounts for a B–F bond length of 143 pm in `"BF"_4^(-)` ion.
संबंधित प्रश्न
If B–Cl bond has a dipole moment, explain why BCl3 molecule has zero dipole moment.
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.
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 Al + NaOH → ?
Write a balanced equation for B2H6 + NH3 → ?
Which of the following oxides is acidic in nature?
Ionisation enthalpy (∆iH1kJ mol–1) for the elements of Group 13 follows the order.
In the structure of diborane ______.
A compound X, of boron reacts with NH3 on heating to give another compound Y which is called inorganic benzene. The compound X can be prepared by treating BF3 with Lithium aluminium hydride. The compounds X and Y are represented by the formulas.
The most commonly used reducing agent is ______.
Explain why the following compounds behave as Lewis acids?
AlCl3
When BCl3 is treated with water, it hydrolyses and forms [B[OH]4]– only whereas AlCl3 in acidified aqueous solution forms [Al(H2O)6]3+ ion. Explain what is the hybridisation of boron and aluminium in these species?
Identify the compounds A, X and Z in the following reactions:
\[\ce{A + 2HCl + 5H2O -> 2NaCl + X}\]
Describe the general trends in the following properties of the elements in Groups 13 and 14.
Atomic size
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.
InCl3, InCl
BCl3 exists as monomer whereas AlCl3 is dimerised through halogen bridging. Give reason. Explain the structure of the dimer of AlCl3 also.
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 ______.
