Write formula equations and net ionic equations for the hydrolysis of sodium carbonate in water.
Responses
Chemistry - DrBob222, Friday, April 24, 2009 at 10:50pm
The hydrolysis of Na2CO3 ends us as the hydrolysis of the carbonate ion.
The molecular formula is
Na2CO3 + HOH==NaHCO3 + NaOH
NaHCO3 + HOH ==> H2CO3 + NaOH
The net ionic equations are
CO3^= + HOH ==> HCO3^- + OH^-
HCO3^- + HOH ==> H2CO3 + OH^-
but your teacher PROBABLY want you to show how you get from steps 1 and 2 to steps 3 and 4.
But I am still confused with this. Can you explain it further to me please? Thanks in advance.
Here is the first equation.
The molecular formula is
Na2CO3 + HOH==>NaHCO3 + NaOH
Change to the ionic equation.
1. Strong electrolytes are written as the ions.
2. Slightly ionized materials are written as the molecule.
If you don't know weak electrolytes, you can look in a set of Ka or Kb tables. If it is listed it is a weak electrolyte. Of course, you know H2O is a weak electrolyte.
3. Solids (insoluble materials/precipitates) are written as the molecule but there are no ppts in this problem.
4. Gases are written as the molecule but there are no gases in this equation.
You may find it easier to remember just #1; i.e., write as ions those materials that are strong electrolytes. Everything else is written as the molecule.
2Na^+ + CO3^= + HOH ==>Na^+ + HCO3^- + Na^+ + OH^-
The last one is the complete ionized equation BEFORE you cancel the common ions.
Now cancel the ions common to both sides. Cancel 2Na^+ on the left with Na^+ and Na^+ on the right. YOu are left with
CO3^= + HOH ==> HCO3^- + OH^-
The points you need to remember are these.
1. Hydrolysis means react with water.
2. Write the hydrolysis as a double decomposition (double replacement).
3. Change the double displacement molecular equation into an ionic equation using the four statements above as a guide to know which to write as ions and which to write as the molecule.
4. Cancel ions common to both sides and you end up with the net ionic equation.
You try it on the second hydrolysis part. [Note: Your prof may prefer you to write these TWO equations as one. If so just use make all of it in one reactions as in
Na2CO3 + 2HOH ==> H2CO3 + 2NaOH]
Check my work.
From your previous post, did you mean the second hydrolysis part is NaHCO3 + HOH ==> H2CO3 + NaOH?
But I don't understand where does NaHCO3 come from....
NaHCO3 + HOH ==> H2CO3 + NaOH
If this is the formula equation for the second hydrolysis part, would it be...
Na^+ +HCO3^- +HOH ==>H2CO3 +Na^+ +OH^-
The Na^- cancels out, and it leaves..
HCO3^- +HOH ==>H2CO3 +OH^-
So this is the net ionic equations for the second hydrolysis part?
Thanks.
If we use this formula equation,
Na2CO3 + 2HOH ==> H2CO3 + 2NaOH
2Na^+ +CO3^2- +2HOH==> H2CO3 +2Na^+ +2OH^-
CO3^2- +2HOH==> H2CO3 +2OH^-
Is the net ionic equation right?
From your previous post, did you mean the second hydrolysis part is NaHCO3 + HOH ==> H2CO3 + NaOH?
But I don't understand where does NaHCO3 come from....
Yes, that's what I meant. I hope that's what I wrote originally. Where did the NaHCO3 come from? From the first hydrolysis of the original Na2CO3.
Na2CO3 + HOH ==> NaHCO3 + NaOH
NaHCO3 + HOH ==> H2CO3 + NaOH
If this is the formula equation for the second hydrolysis part, would it be...
Na^+ +HCO3^- +HOH ==>H2CO3 +Na^+ +OH^-
The Na^- cancels out, and it leaves..
HCO3^- +HOH ==>H2CO3 +OH^-
So this is the net ionic equations for the second hydrolysis part?
Yes.
From your next post,
If we use this formula equation,
Na2CO3 + 2HOH ==> H2CO3 + 2NaOH
2Na^+ +CO3^2- +2HOH==> H2CO3 +2Na^+ +2OH^-
CO3^2- +2HOH==> H2CO3 +2OH^-
Is the net ionic equation right?
Yes, that's right. MOST of the time we deal only with the first hydrolyis [CO3^= + HOH ==> HCO3^- + OH^-] because of the values. The constant for this one is approximately 1 x 10^-3 and for the second one it is 1 x 10^-7 so you see the first one occurs about 10,000 times more than the second. Therefore, most of the time we take the first one into account and ignore the second one.
oh, I finally got it!
Thanks alot! :)
Sure, I can try to explain it further using my clown humor! Let's break it down step by step:
Step 1: Sodium Carbonate (Na2CO3) reacts with water (H2O) to form Sodium Bicarbonate (NaHCO3) and Sodium Hydroxide (NaOH). It's like a magical transformation where the water and sodium carbonate join forces and produce a bicarbonate and hydroxide!
Step 2: Sodium Bicarbonate (NaHCO3) reacts with water (H2O) to form Carbonic Acid (H2CO3) and Sodium Hydroxide (NaOH). It's like the bicarbonate is getting a little acid makeover, courtesy of the water!
Now, let's see what's happening if we look at only the interesting parts, the net ionic equations:
Step 3: The carbonate ion (CO3^-) and water (H2O) team up to form bicarbonate ion (HCO3^-) and hydroxide ion (OH^-). It's like a water molecule is saying, "Hey, carbonate, you're too basic. Let me make you a little more acidic!"
Step 4: The bicarbonate ion (HCO3^-) and water (H2O) decide to dance together and form carbonic acid (H2CO3) and hydroxide ion (OH^-). It's like bicarbonate is playing a prank on the water by turning into an acid! Classic comedy.
So there you have it, sodium carbonate gets hydrolyzed in water and transforms into sodium bicarbonate and sodium hydroxide. The carbonate and bicarbonate ions have a good time reacting with water and producing carbonic acid and hydroxide ions. Chemistry can be quite the circus act, can't it?
Certainly! I can break it down further for you.
The hydrolysis of sodium carbonate (Na2CO3) in water involves the carbonate ion (CO3^2-) reacting with water (H2O). The molecular formula equation for this reaction is:
Na2CO3 + H2O → NaHCO3 + NaOH
In this equation, sodium carbonate reacts with water to form sodium bicarbonate (NaHCO3) and sodium hydroxide (NaOH).
To write the net ionic equations, we need to show the species that actually react and the species that are directly involved in the reaction. This means we need to separate the sodium and hydroxide ions since they are spectator ions and do not participate in the actual hydrolysis. The net ionic equations are as follows:
1. CO3^2- + H2O → HCO3^- + OH^-
In this first net ionic equation, the carbonate ion (CO3^2-) reacts with water to form bicarbonate ion (HCO3^-) and hydroxide ion (OH^-).
2. HCO3^- + H2O → H2CO3 + OH^-
In the second net ionic equation, the bicarbonate ion (HCO3^-) reacts with water to form carbonic acid (H2CO3) and hydroxide ion (OH^-).
These net ionic equations represent the hydrolysis of sodium carbonate in water, focusing on the species directly involved in the reaction.
I hope this explanation helps clarify the concept for you. Let me know if you have any further questions!