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प्रश्न
Account for the following observations:
The +1 oxidation state of thallium is more stable than its +3 state.
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उत्तर
As we move down the group in group 13 the participation of s-electrons in bond formation decreases the primary reason behind this is the inert pair effect. In this the p-electrons take part in bond formation and more energy is required to unpair the valence electrons to make them participate in bonding. Due to this the lower oxidation state of elements becomes stable than the higher oxidation state. As for thallium, +1 oxidation state is more stable than +3.
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संबंधित प्रश्न
How can you explain higher stability of BCl3 as compared to TlCl3?
If B–Cl bond has a dipole moment, explain why BCl3 molecule has zero dipole moment.
What happens when BF3 is reacted with ammonia?
How would you explain the lower atomic radius of Ga as compared to Al?
What do you understand by inert pair effect?
Write a balanced equation for B2H6 + NH3 → ?
In the structure of diborane ______.
Which of the following statements are correct. Answer on the basis of Figure.
(i) The two birdged hydrogen atoms and the two boron atoms lie in one plane;
(ii) Out of six B – H bonds two bonds can be described in terms of 3 centre 2-electron bonds.
(iii) Out of six B – H bonds four B – H bonds can be described in terms of 3 centre 2 electron bonds;
(iv) The four-terminal B – H bonds are two centre-two electron regular bonds.
Explain why the following compounds behave as Lewis acids?
BCl3
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?
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:
Electron gain enthalpy of chlorine is more negative as compared to fluorine.
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 the properties mentioned in Column II.
| Column I | Column II |
| (i) \[\ce{BF^{-}4}\] | (a) Oxidation state of central atom is +4 |
| (ii) AICI3 | (b) Strong oxidising agent |
| (iii) SnO | (c) Lewis acid |
| (iv) PbO2 | (d) Can be further oxidised |
| (e) Tetrahedral shape |
Account for the following observations:
Though fluorine is more electronegative than chlorine yet BF3 is a weaker Lewis acid than BCl3
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.
AlCl3 , AlCl
Boron compounds behave as Lewis acids because of their ______.
