Why The phenoxide ion is more stable than phenol ?

The phenoxide ion is more stable than phenol, due to greater dispersal of negative charge, therefore. Equilibrium get shifted to forward direction. whereas alkoxide ion is less stable than alcohols due to intensification of negative charge, so equilibrium get shifted towards backward direction. Hence phenols are more acidic than alcohols. 

Related Questions:

Benzamide is less easily hydrolysed than methyl benzoate. Why ?

Highly branched carboxylic acids are less acidic than unbranched acids. Explain why?

Phenoxide ion is more stable than an alkaoxide. why?

Which is more stable? CH3-CH2+ (Ethyl carbocation) or CH2=CH+ (Vinyl carbocation)? And why?

No Doubt, Ethyl carbocation (CH3-CH2+) is more stable than vinyl carbocation (CH2=CH+). The greater stability of CH3-CH2+ carbocation over vinyl carbocation because the positive charge on the CH2 is stabilised by the inductive effect as well as hyperconjugation  from the neighbouring carbon atom.
But in case of CH2=CH+. The two carbon atoms involved are sp2 hybridised. An sp2 hybridised carbon atom is more electronegative which increases positive charge and increases as the s-character of a hybridised carbon atom increases. As the the result inductive effect decreases by the neighbouring carbon atom. 

Why Guanidine behave as the strongest base among neutral compounds?. explaine the remarkable basicity of guanidine.

Basicity of Guanidine:

Guanidine is the strongest base among neutral compounds:

The remarkable basicity of guanidine is attributed to the fact that the positive charge on the guanidinium ion is delocalized equally over the three nitrogen atoms, as shown by

these three equivalent resonating  structures:

Basicity of nitrogen can be increased by attachment topi-donors (NH₂) group. These two pi-donating NH₂groups donate electron density to the (pi-accepting) C=NH. Hence, the guanidinium ion is a highly stable cation.

What is Guanidine and its structure , name amino acid which contains guanidine group ?

Guanidine is strongest organic nitrogenous compound with the formula HNC(NH₂)₂. Guanidine is analogue of carbonic acid. That is, the C=O group in carbonic acid is replaced by a C=NH group, and each OH is replaced by a NH₂ group.

A guanidine group also appears in larger organic molecules, including on the side chain of arginine (a basic amino acid).

It is a colourless solid that dissolves in polar solvents. It is a strong base that is used in the production of plastics and explosives. It is found in urine as a normal product of protein metabolism.

What is correct acidic strengths order of the haloforms acids ? Give correct explanation.

We know that acidic strength of the acid also depends upon stability of conjugate bases, so for relative strength of acid, we need to check the relative stabilities of their conjugate bases.

                                                     CF₃^-, CCl₃^-, CBr₃^- CI₃^-

We are expecting the acidic strength haloform acids asCHF₃, CHCl₃, CHBr₃, CHI₃ in decreasing order. Because Fluorine is most electronegative atom so it would be stabilize CF₃^- more, as electronegativity decreases from F to I the stability of conjugate -ve ion would be but that is not correct the actual order isCHCl₃ > CHF₃ > CHBr₃ > CHI₃.

This is because there is effective back bonding in CCl₃-and hence the negative charge partially gets stabilised by back donation to the vacant 3d orbitals of Cl. Thus, CHCl₃ is a stronger acid than CHF₃ and also among them due to 2pπ-3dπ back bonding.

The acidic strengths of the other three haloforms can be compared the inductive effects of their anions. F is very electronegative and hence stabilises the negative charge on the C atom. So, CHF₃ is a better acid than CHBr₃, and the least acidic is CHI₃.

 The overall acidic strength order is:

     CHCl₃ > CHF₃ > CHBr₃ > CHI₃.