While only partially dissociating in water, why does a weak acid completely react with a strong base?
Whereas water is not strong enough to pull a H[math]^+[/math] ion from all the available weak acid molecules, a strong base is definitely strong enough to do so.Practically, the acid and the base molecule do not even have to come close in the solution for this to happen. The weak acid is in a continuous equilibrium in which some of the molecules lose their H[math]^+[/math] ion and others regain it, all the time, and at the same rate. If a strong base is present, the H[math]^+[/math] will be taken away by the base, and therefore the protonation of the acid’s conjugated base will slow down. This will cause a net deprotonation of the weak acid until it is all gone or until the strong base is all used.
Formic acid is weak acid found in insect stings. It partially dissociates in water according to the reaction?
...HCHO2 <->CHO2- + H+ -What is the dissociation constant (Ka) for the acid? -What is the value of Ka if a solution of formic acid contains .2M HCHO2, 0.006 M CHO2- and 0.006 M H+ Also.. what is the ph of the solution at the concentrations given?? Thank you, any help is greatly greatly appreciated!!!
Why do strong acids completely dissociate into ions in water?
Strong acids are in equilibrium with their conjugate bases. However, the free energy of dissociation (ie. the Ka) is so high that for all practical purposes the acid is completely dissociated. The strength of the acid is largely determined by the stability of the anion being generated. If you look at the traditional strong mineral acids, they have extremely stable counteranions. For example HCl dissociates into H+ and Cl-. For mineral acids, the larger the counteranion, the stronger the acid. This is because a larger sphere can more effectively disperse the negative charge than a smaller sphere. Hence the reason HI is a strong acid and HF is a weak acid.
What is the difference between strong acids or bases and weak acids or bases?
Firstly, the definitions:Acids dissolve in water to form H+ ions.Bases dissolve in water to form OH- ions.Lets take a look at acids - A strong acid (HCl) vs a weak acid (CH3COOH).A strong acid will fully dissociate in water to form H+ ions.HCl + H2O---> H3O+ + Cl- This reaction is non-reversible. After dissolution, only a very very minute concentration of HCl itself remains in the solution, as most of the diluted HCl has dissolved into ions.Ka = [H+] [Cl-] / [HCl]A weak acid, however undergoes a reversible reaction as it only partially dissociates.CH3COOH + H2O <---> CH3COO- + H3O+Ka = [CH3COO-] [H3O+] / [CH3COOH]As Ka is a constant, as more CH3COOH is added, by Le Chatelier's Principle, in this reversible reaction, the system will aim to shift the equilibrium as such to reverse the change. Therefore, less CH3COOH than added will dissociate into its constituent ions.Ionic equilibrium can be explained by http://www.chem1.com/acad/webtex...The reason why one reaction is reversible and the other is not can be explained by http://chemed.chem.purdue.edu/ge...The favourability of a reaction (whether forward or reverse) will depend largely on the temperature and change in entropy.The same applied for bases. The only difference is that the base dissociates to form OH- ions instead.Strong and weak bases will depend likewise on whether the reaction is reversible (there are exceptions to this of course)NaOH + H2O ---> Na+ + OH- + H2OKb = [Na+] [OH-] / [NaOH]
Acids and bases- strong or weak?
Strong electrolytes are completely dissociated into ions in water. The acid or base molecule does not exist in aqueous solution, only ions. So if you put a strong acid/base in water it dissociates into ions. Weak electrolytes are incompletely dissociated. Strong acids completely dissociate in water, forming H+ and an anion. There are six strong acids. The others are considered to be weak acids. You should commit the strong acids to memory: HCl - hydrochloric acid HNO3 - nitric acid H2SO4 - sulfuric acid 100% dissociation isn't true as solutions become more concentrated. If the acid is 100% dissociated in solutions of 1.0 M or less, it is called strong. Weak Acids A weak acid only partially dissociates in water to give H+ and the anion. Examples of weak acids include hydrofluoric acid, HF, and acetic acid, CH3COOH. Weak acids include: Strong Bases Strong bases dissociate 100% into the cation and OH- (hydroxide ion). The hydroxides of the Group I and Group II metals usually are considered to be strong bases. NaOH - sodium hydroxide KOH - potassium hydroxide *Ca(OH)2 - calcium hydroxide * These bases completely dissociate in solutions of 0.01 M or less. The other bases make solutions of 1.0 M and are 100% dissociated at that concentration. There are other strong bases than those listed, but they are not often encountered. Weak Bases Examples of weak bases include ammonia, NH3, and diethylamine, (CH3CH2)2NH. Most weak bases are anions of weak acids. Weak bases don't make OH- ions by dissociation. Instead, they react with water to make OH- ions. Too much info?
What does it mean if an acid or base is weak?
Strong acids and Strong bases completely dissociates in water.e.g HCl(a strong acid) and NaOH(a strong base).The following dissociation of strong acid and base in water. HCl==>H^+ + Cl^-. NaOH==>Na^+ + OH^- . while Weak acids and Weak bases partially dissociates in water. e.g CH3COOH(a weak acid) and Na2CO3(a weak base). The following dissociation of weak acid and base in water.CH3COOH==>CH3COO^- + H^+.Na2CO3==>2Na^+ + CO3^2-.Take care