- #31
AdityaDev
- 527
- 33
After reading it, you possibly won't come back to the thread.
Why reducing nature of hydrides increases down a group?
Click For Summary
Discussion Overview
The discussion revolves around the contrasting reducing nature of hydrides and oxides as one moves down a group in the periodic table. Participants explore the reasons behind these trends, focusing on the bond dissociation energies, electropositivity of metals, and the implications for acidity and basicity of various compounds. The conversation encompasses theoretical aspects and examples from different groups, particularly the p-block elements.
Discussion Character
- Debate/contested
- Conceptual clarification
- Technical explanation
Main Points Raised
- Some participants note that the reducing nature of hydrides increases down a group, while for oxides, it decreases.
- It is proposed that increasing metal electropositivity allows for a greater negative charge on hydrides.
- Concerns are raised about the bond dissociation energy of hydrides decreasing down a group, which is suggested to correlate with increasing reducing nature.
- One participant questions the relationship between bond strength and oxidizing power of oxides, noting conflicting factors such as the inert pair effect and the ability of larger atoms to stabilize oxide ions.
- There is a discussion about the basicity of hydrides decreasing down groups 15 and 16, with references to lone pairs and Lewis base qualifications.
- Participants express confusion about the differences in behavior between hydrides and oxides, particularly regarding acidity and basicity across different groups.
- Examples are requested to clarify the trends in reducing strength and basicity of oxides and hydrides.
- Some participants mention the instability and reactivity of group 17 oxides, suggesting they are primarily oxidizing agents.
- There is a reference to the need for theoretical understanding versus experimental observations regarding the behavior of oxides and hydrides.
Areas of Agreement / Disagreement
Participants do not reach a consensus on the reasons behind the differing trends in reducing nature between hydrides and oxides. Multiple competing views and uncertainties remain regarding the underlying principles and examples discussed.
Contextual Notes
Participants express confusion over various factors influencing the reducing nature and basicity of hydrides and oxides, including bond dissociation energies, the inert pair effect, and the stability of different oxides. There are unresolved questions about the applicability of certain concepts across different groups in the periodic table.
- #32
Raghav Gupta
- 1,010
- 76
Alas. I don't have that.AdityaDev said:
Can you tell only why metallic oxides are basic in nature.
- #33
AdityaDev
- 527
- 33
You can get the ebooks online at cheap rates.
metallic oxides are basic in nature because they react with water to form metal hydroxides which are basic in nature.
metallic oxides are basic in nature because they react with water to form metal hydroxides which are basic in nature.
- #34
Raghav Gupta
- 1,010
- 76
So why metallic hydrides are not basic?AdityaDev said:
- #35
AdityaDev
- 527
- 33
I have never read about basic nature of hydrides. They are known to be reducing agents. Alkali metal hydrides react with water liberating hydrogen gas and a hydroxide. Also such hudrides are called salt-like hydrides not acidic or basic hydrides. But non metal hydrides are basic like NH3.
- #36
Raghav Gupta
- 1,010
- 76
But when comparing acidity of NH3,PH3,AsH3,SbH3 we say that Down the group acidity increases which is analogue to up the group basicity increases?AdityaDev said:
- #37
AdityaDev
- 527
- 33
That is because of low electron density at central atom. As size increases, the electron density around central metal atom decreases hence basicity decreases.
- #38
Raghav Gupta
- 1,010
- 76
So why that statement is wrong in case of oxides of that group?AdityaDev said:
- #39
Raghav Gupta
- 1,010
- 76
In continuation with post #25 why then group 16? Wiki is showing that they are not hydrides but like hydrogen selenide, hydrogen oxide etc.Jack2 said:
- #40
Jack2
- 5
- 1
Hydride mean a hydrogen atom with a negative charge .Raghav Gupta said:
In all halogens , hydrogen has +1 charge . They are called acids , not hydrides .
In group 16 , the lower elements are metallic ( having EN less than 2.1 ) so their compounds can be called hydrides . So I made a generalized statement .
But surely halogen groups don't form hydrides .
- #41
Raghav Gupta
- 1,010
- 76
Why the generalized statement , when only in that group Polonium is a metal? It should be called a exception from 16 group.
and what about this?
and what about this?
Raghav Gupta said:I was reading that but there the wikipedian has written citation needed where he/she is saying following compounds are hydrogen and not hydrides, means he/she can be lying.
Basically what I meant in this thread is hydrogen bonding to elements whether it would be a hydride or hydrogen that's all nomenclature but a hydrogen is hydrogen.
Now one can also argue with oxides, there are peroxides, superoxides. But what really matter is linkage of element with oxygen.
- #42
Borek
Mentor
- 29,180
- 4,612
To all - please keep your posts on topic and if you have new questions, start a new thread.
- #43
Raghav Gupta
- 1,010
- 76
Borek said:
I few days ago started a new thread but got only one reply and none then.
Even if you have said I don't know it would have been fine( I know elders hesitate to say this sometimes but then also basic etiquettes are required).
Anyway I agree with you that for new questions new thread must be started and by the way excluding 2 threads you have helped me a lot in chemistry.
But any comment or reply for first para?
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