[bmthog]

Please help me explain why the acidity as follows:

1) H₂CO₃=OH-COOH < CH₃COOH
+ Me is releasing group while OH is withdrawing group ?

2) EtOH> HCCH> NH₃> C₂H₄> CH₄
 
I can't explain these stuffs (

[bmthog]

Anybody please help me

[Honclbrif]

You're considering inductive effects, but are there any resonance effects you should be considering?

[orgopete]

For 1), I agree with the electron donation of a CH3 group reducing the acidity.

For 2), I would like to split this into two problems.

EtOH>NH3>CH4 and HC≡CH>CH2=CH2>CH4

For the first, it is a simple matter of as the protons surrounding CH4 are placed into the nucleus, the nuclear charge increases the electron withdrawing properties. Therefore ethanol is more acidic than ammonia and in turn methane. The bond lengths also lengthen as the acidity decreases. This matches the electron withdrawing properties. If we were to include fluorine with HF, then we would find HF has the largest number of protons in its nucleus (in that row), the shortest bond length, and the most acidity.

For the second set, we must conclude from the acidity that an acetylenic carbon is more electron withdrawing than a vinylic or alkyl carbon.

If we combine the series together, we find that an acetylenic carbon jumps past ammonia in acidity. I am not trying to explain why it is, but rather to marvel at the effect. A double bond changes a carbon in such a way that the acidity is increased and this effect is extended further in a triple bond.