Skip to main content

Why is the equivalence point of the reaction between hydrochloric acid and sodium carbonate "somewhat acidic"?

The balanced chemical equation for the described reaction is as follows:


`HCl + Na_2CO_3 -> H_2CO_3 + NaCl ` .


The equivalence point is not at pH 7 but is slightly acidic.


The equivalence point is defined as the point during titration wherein the moles of added acid (or base) are equal to the moles of the base (or acid) being titrated. In titration of strong acids and bases, like the reaction of NaOH and...

The balanced chemical equation for the described reaction is as follows:


`HCl + Na_2CO_3 -> H_2CO_3 + NaCl ` .


The equivalence point is not at pH 7 but is slightly acidic.


The equivalence point is defined as the point during titration wherein the moles of added acid (or base) are equal to the moles of the base (or acid) being titrated. In titration of strong acids and bases, like the reaction of NaOH and HCl, the product is NaCl, a neutral salt, and water, a neutral substance. This is true for any strong acid and strong base -- the products will always be a neutral salt and water -- and hence, the pH of the resulting solution at the equivalence point is 7.


This is not the case, however, if one of the reacting species isn't a strong acid or a strong base. Sodium carbonate dissociates in water into its ions -- the sodium ion and the carbonate ion. The carbonate ion is a weak base. Since it is  a weak base, upon reaction with HCl, it produces its conjugate acid. The conjugate acid, just like any acid in a solution, will react with water to produce more hydronium ions. The generation of this extra hydronium makes the equivalence point of this given titration reaction slightly acidic.


In general, if a reaction is between a strong acid and a strong base, the equivalence point will be at pH 7. If it's between a strong acid and a weak base, it will be acidic. If it's between a weak base and a strong base, it will be basic.

Comments

Post a Comment

Popular posts from this blog

What is the meaning of "juggling fiends" in Macbeth?

Macbeth is beginning to realize that the three witches have been deceiving him since he first encountered them. Like jugglers, they have kept changing their forecasts in order create confusion. This is particularly apparent when the Second Apparition they raise in Act IV,   Scene 1 tells him that no man of woman born can overcome him in hand-to-hand battle--and then Macbeth finds himself confronted by the one man he has been avoiding out of a... Macbeth is beginning to realize that the three witches have been deceiving him since he first encountered them. Like jugglers, they have kept changing their forecasts in order create confusion. This is particularly apparent when the Second Apparition they raise in Act IV,   Scene 1 tells him that no man of woman born can overcome him in hand-to-hand battle--and then Macbeth finds himself confronted by the one man he has been avoiding out of a sense of guilt, and that man tells him: Despair thy charm. And let the angel whom thou still hast serve...
Post a Comment
Read more

What are some external and internal conflicts that Montag has in Fahrenheit 451?

 Montag, the protagonist of Fahrenheit 451, faces both external and internal conflicts throughout the novel. Some examples of these conflicts are: External Conflicts: Conflict with the society: Montag lives in a society that prohibits books and critical thinking. He faces opposition from the government and the people who enforce this law. Montag struggles to come to terms with the fact that his society is based on censorship and control. Conflict with his wife: Montag's wife, Mildred, is completely absorbed in the shallow and meaningless entertainment provided by the government. Montag's growing dissatisfaction with his marriage adds to his external conflict. Conflict with the fire captain: Montag's superior, Captain Beatty, is the personification of the oppressive regime that Montag is fighting against. Montag's struggle against Beatty represents his external conflict with the government. Internal Conflicts: Conflict with his own beliefs: Montag, at the beginning of th...
Post a Comment
Read more

In A People's History of the United States, why does Howard Zinn feel that Wilson made a flimsy argument for entering World War I?

"War is the health of the state," the radical writer Randolph Bourne said, in the midst of the First World War. Indeed, as the nations of Europe went to war in 1914, the governments flourished, patriotism bloomed, class struggle was stilled, and young men died in frightful numbers on the battlefields-often for a hundred yards of land, a line of trenches. -- Chapter 14, Page 350, A People's History of the United States Howard Zinn outlines his arguments for why World War I was fought in the opening paragraph of Chapter 14 (referenced above). The nationalism that was created by the Great War benefited the elite political and financial leadership of the various countries involved. Socialism, which was gaining momentum in Europe, as was class struggle, took a backseat to mobilizing for war. Zinn believes that World War I was fought for the gain of the industrial capitalists of Europe in a competition for capital and resources. He states that humanity itself was punished by t...
Post a Comment
Read more