Advertisements
Advertisements
प्रश्न
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.
Advertisements
उत्तर
Hydrogen fluoride (HF) is a covalent compound and has a very strong intermolecular hydrogen-bonding. Thus, it does not provide ions and aluminium fluoride (AlF) does not dissolve in it. Sodium fluoride (NaF) is an ionic compound and when it is added to the mixture, AlF dissolves. This is because of the availability of free F–. The reaction involved in the process is:
\[\ce{AlF_3 + 3NaF -> \underset{Sodium hexafluoroaluminate (III)}{Na3[AlF6]}}\]
When boron trifluoride (BF3) is added to the solution, aluminium fluoride precipitates out of the solution. This happens because the tendency of boron to form complexes is much more than that of aluminium. Therefore, when BF3 is added to the solution, B replaces Al from the complexes according to the following reaction:
\[\ce{Na3[AlF6] + 3BF3 -> 3Na[BF4] + AIF3}\]
संबंधित प्रश्न
If B–Cl bond has a dipole moment, explain why BCl3 molecule has zero dipole moment.
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 Al + NaOH → ?
Dry ice is ______.
Explain why the following compounds behave as Lewis acids?
BCl3
Explain the following:
PbX2 is more stable than PbX4.
Explain the following:
Tl (NO3)3 acts as an oxidising agent.
Identify the compounds A, X and Z in the following reactions:
\[\ce{X ->[Δ][370 K] HBO2 ->[Δ][> 370 K] Z}\]
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.
Metallic character
Account for the following observations:
Though fluorine is more electronegative than chlorine yet BF3 is a weaker Lewis acid than BCl3
Account for the following observations:
PbO2 is a stronger oxidising agent than SnO2
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.
TlCl3, TlCl
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
Boron fluoride exists as BF3 but boron hydride doesn’t exist as BH3. Give reason. In which form does it exist? Explain its structure.
Taking stability as the factor, which one of the following represents the correct relationship?
