observer1 Posted January 19, 2023 Posted January 19, 2023 (edited) The reaction between Ca(CH3COO)2 + Na2CO3 ---> CaCO3 + 2CH3COONa But why can't the same displacement reaction happen when NaHCO3 is added to Ca(CH3COO)2 Why does it show that no reaction happens when they are mixed? (type it in google) Edited January 19, 2023 by observer1
chenbeier Posted January 19, 2023 Posted January 19, 2023 (edited) Develop the equation. What would you get? Ca(CH3COO)2 + NaHCO3 ---> Further questions? Edited January 19, 2023 by chenbeier
exchemist Posted January 19, 2023 Posted January 19, 2023 4 hours ago, observer1 said: The reaction between Ca(CH3COO)2 + Na2CO3 ---> CaCO3 + 2CH3COONa But why can't the same displacement reaction happen when NaHCO3 is added to Ca(CH3COO)2 Why does it show that no reaction happens when they are mixed? (type it in google) You don't seem to be taking in the content of previous replies on this matter. 1) CaCO3 is largely insoluble. So a solution of ions containing Ca²⁺ and CO3²⁻ will precipitate out CaCO3. So that's why that one happens. As I explained before, if all the combinations of salts are soluble, all you get is a mixture of dissolved ions, as there is nothing to cause one compound to separate from the mixture. 2) Ca(HCO3)₂ does not exist in the solid state, as I pointed out on one of your previous threads. https://en.wikipedia.org/wiki/Calcium_bicarbonate If you want to know why it does not exist, that's a more complicated question, though we could discuss the reasons. My guess is it will be due to the difficulty in accommodating 2 large monovalent anions in a crystal structure with one smallish divalent cation. In other words the lattice energy is expected to be low, making formation of this compound in the solid phase energetically unattractive, relative to other options.
chenbeier Posted January 19, 2023 Posted January 19, 2023 One thing more Ca(CH3COO)2 + NaHCO3 ---> CaCO3 + CH3COONa +CH3COOH!!!! Acetic acid is to acidic that this reaction appears. It would work in opposit direction more or less.
exchemist Posted January 19, 2023 Posted January 19, 2023 1 hour ago, chenbeier said: One thing more Ca(CH3COO)2 + NaHCO3 ---> CaCO3 + CH3COONa +CH3COOH!!!! Acetic acid is to acidic that this reaction appears. It would work in opposit direction more or less. Not sure I follow this. Do you mean that because acetic acid is a weak acid, an aqueous solution of any acetate will be mostly in the form of undissociated acetic acid, thus making acetate salts net absorbers of H+ ions - and therefore basic?
chenbeier Posted January 19, 2023 Posted January 19, 2023 No, compare the acidity or the pKa of NaHCO3 and CH3COOH Who will win the game if mixed. In my opinion Hydrogen carbonate is not able to expell acetic acid. The opposit is the case. Even CO2 development takes place.
observer1 Posted January 19, 2023 Author Posted January 19, 2023 so is is VERY unlikely for the reaction to occur or it it basically not possilbe?
chenbeier Posted January 19, 2023 Posted January 19, 2023 If you dont get precipitation then it will not occur.
exchemist Posted January 19, 2023 Posted January 19, 2023 (edited) 3 hours ago, chenbeier said: No, compare the acidity or the pKa of NaHCO3 and CH3COOH Who will win the game if mixed. In my opinion Hydrogen carbonate is not able to expell acetic acid. The opposit is the case. Even CO2 development takes place. OK, pKa of acetic acid is lower, so acetate will not tend to abstract H+ from HCO3-. Ah, so what you mean is that acetic acid would protonate HCO3-, leading to formation of carbonic acid, which then decomposes to CO2 and water. Yes, indeed. But what he have here is acetate not acetic acid. So I'm still not quite following you. Edited January 19, 2023 by exchemist
chenbeier Posted January 19, 2023 Posted January 19, 2023 (edited) We have acetate in this case the Calcium acetate and sodium hydrogen carbonate. To get Calciumcarbonate the sodium and the hydogen has to react with the acetate. This means sodium acetate and acetic acid has to be built. But Acetic acid will not get built because it would react directly with carbonate to CO2 back. So calcium acetate will remain. Ca(CH3COO)2 + NaHCO3 ---> CaCO3 + CH3COONa +CH3COOH!!!! This will not happen. Edited January 19, 2023 by chenbeier
observer1 Posted January 20, 2023 Author Posted January 20, 2023 so in that reaction, the acetic acid will again react with CaCO3 to form calcium acetate again then why doesn't this reaction occur? Ca(CH3COO)2 + NaHCO3 ---> CaCO3 + CH3COONa + H2 here the hydrogen leaves as gas
chenbeier Posted January 20, 2023 Posted January 20, 2023 The equation is not balanced. Where you get the second hydrogen from. One Acetate is missing. It is not a redox reaction.
chenbeier Posted January 20, 2023 Posted January 20, 2023 No the problem you didn't balanced the equation. The solution already given above.
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now