Weak conjugate base

Strong acid + strong base - weak (conjugate) base + weak (conjugate) acid. 

Weak acids (WA) have strong conjugate bases (SB), while strong acids (SA) have weak conjugate bases (WB). The weaker the acid or base, the stronger its conjugate. 

This can be construed as the competition between the bases HX and Y" for protons. It should be apparent that the more powerful HY is as a proton donor, the weaker will be Y as a proton acceptor. In other words, a strong acid will have a weak conjugate base and vice versa. It is often more convenient to rationalise the relative strengths of acids in terms of the proton affinities of their conjugate bases. We look first at acids in aqueous solution, and then at acid/base and other equilibria in non-aqueous polar solvents. 

Because the product of Ka times Kb is a relatively small number, either the acid or its conjugate base can be strong. But if one is strong, the other must be weak. Thus, a strong acid must have a weak conjugate base. 

Triflate, tosylate and mesylate are the anions of strong acids. The weak conjugate bases are poor nucleophiles. Nucleophilicity increases in parallel with the base strength. Thus, amines, alcohols and alkoxides are very good nucleophiles. Base strength is a rough measure of how reactive the nonbonding electron pair is thus, it is not necessary for a nucleophile to be anionic. 

Strong acid pKa = 0.63 Weak Conjugate base (stabilized)... 

To summarize, strong acids yield weak conjugate bases while weak acids yield relatively strong conjugate bases. 

The correct answer is (C). HC1 is a very strong acid, which means that the chloride ion is a very weak conjugate base. This means the solution is not a buffer solution. The potassium chloride is really a distracter in this question. Although CP is present in each salt, the common-ion effect is only seen in equilibrium systems. The reverse reaction for the dissociation of either of these two would be so slight it would be negligible. However, because KC1 does nothing to neutralize the acid, the solution would be both acidic and not a buffer. 

Looking at the reaction of an imidazolium salt with mercury(ll) acetate to form the [Hg(NHC)j] complex, the original reaction of Wanzlick and Schonherr [3], we are left with a small mystery. Why could the weak conjugate base acetate (pK 4.75 in water) deproto-nate the much weaker acid imidazolium ... 

A strong acid readily donates a proton, forming a weak conjugate base. 

Because strong acids form weak conjugate bases, the basicity of conjugate bases increases with increasing pKg of their acids. 

Salts are ionic compounds that dissociate in water. Often, when salts dissociate, they create acidic or basic conditions. The pH of a salt solution can be predicted qualitatively by comparing the conjugates of the respective ions. Just keep in mind that strong acids have weak conjugate bases and strong bases have weak conjugate acids. 

This reaction does not occur to any great extent since the Cl- is the conjugate base of a strong acid, namely HCl. The Cl- is therefore a very weak conjugate base and its reaction with water can be neglected. 

Strong acids have a low pAfa and have weak conjugate bases. 

The ion or molecule formed by the loss of a proton from an acid is the conjugate base. Strong acids form weak conjugate bases and weak acids form strong conjugate bases. 

An analogous reaction will be shown by a positive ion which can act as an acid in water solution to form its weak conjugate base. Thus, a solution of ammonium chloride would be acidic because of the reaction... 

A buffer solution is a combination of either a weak acid and its weak conjugate base (supplied by a salt) or a weak base and its weak conjugate acid (supplied by a salt) the solution reacts with small amounts of added acid or base in such a way that the pH of the solution remains nearly constant. Buffer systems play a vital role in maintaining the pH of body fluids. 

Conjugate acid-base pairs. Strong acids have weak conjugate bases strong bases have weak conjugate acids. 

A strong acid contains a relatively weak conjugate base—one that has a low attraction for protons. 

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