Question

Rank the stability of the following conjugate bases from MOST to LEAST stable (Most = 1, Least = 5)

Answer 1

When an acid loses a proton, it forms its conjugate base as-

HA (acid) -------------> H⁺ + A^- (conjugate base)

Now if we say a conjugate base is more stable, that means its acid must have lost the proton very easily and fast to produce a stable compound. So we can say stable conjugate bases are formed from stronger acid which loses proton very easily.

Again in organic compounds, generally we will find a negative charge as base. So here we also have to see that the formed negative charge is more stable on the atom or not. If it is present on its stable position, then the conjugate base is more stable.

So the general rule is- Negative charges are more stable on electronegative atoms than on other atoms-

Now from the given structures-

① A negative change is more stable on o-atom than n-atom as Orggen is mare eledomegatire they Métrogey o is more stable than cu E l Simetarly negative charge on M-atom is more stable than negative change on Catona stable ② Again As the spor s-character increased es a molecule, its a codor strength increases ! so A sp-orbital (Alkyne), sp² abikil a Calkene) spesbets (Alkane) more stable more stable least stabl)

so of v final decreasing order it stability conjugate base es t a > >9 >=0> NH