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    how do i work out the product of H3PO4 + NaOH ? ? ? ?
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    Well as this is a neutralisation reaction you're goingto make a salt and water. So basically as you're making water, you know that's 2 hydrogens and an oxygen taken care with then you have 2 hydrogens, 4 oxygens, phosphorus and sodium left. This compound then has the formula of NaH2PO4.

    H3PO4 + NaOH --> NaH2PO4(aq) + H2O
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    (Original post by FrooshGuitar)
    Well as this is a neutralisation reaction you're goingto make a salt and water. So basically as you're making water, you know that's 2 hydrogens and an oxygen taken care with then you have 2 hydrogens, 4 oxygens, phosphorus and sodium left. This compound then has the formula of NaH2PO4.

    H3PO4 + NaOH --> NaH2PO4(aq) + H2O
    thanks for the helps ,but how would i apply the same method for e.g.

    siO2 + NaOH ?
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    (Original post by HG1)
    how do i work out the product of H3PO4 + NaOH ? ? ? ?
    technically you could end up with three different salts:
    Na3PO4
    NaHPO4
    Na2H2PO4

    however in a level syllabus im pretty sure you would just want Na3PO4 because H3PO4 is a strong acid therefore fully dissociates which leaves you with PO4(3-) ion hence sodium-phosphate
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    (Original post by milutin767)
    technically you could end up with three different salts:
    Na3PO4
    NaHPO4
    Na2H2PO4

    however in a level syllabus im pretty sure you would just want Na3PO4 because H3PO4 is a strong acid therefore fully dissociates which leaves you with PO4(3-) ion hence sodium-phosphate
    Thanks , im still confused as to how these are worked out or do you just have to memeorise them ?
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    (Original post by HG1)
    Thanks , im still confused as to how these are worked out or do you just have to memeorise them ?
    well i wouldn't memorise the actual reaction but principle is pretty much the same

    H3PO4 is an acid therefore releases protons in solution:
    H3PO4---> H+ + H2PO4(-)
    H2PO4----->H+ + HPO4(2-)
    HPO4(2-)---->H+ + PO4(3-)

    so NaOH has only one OH group:
    NaOH---->Na+ + OH-

    so you can get:
    NaH2PO4 (acidic salt)
    Na2HPO4 (acidic salt)
    Na3PO4 (neutral salt)
    (i see a made a mistake in the previous answer sorry about that)

    i don't think you need to know that but essentially neutralisation reaction is the one between acid and a base to form a salt and water
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    Yeah I tried working them out once and it takes too much effort to make sense of it (though i managed it in the end). Im just gonna learn them

    btw i learnt the ionic equaions so i can apply them to several compounds
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    (Original post by Nayzar)
    Yeah I tried working them out once and it takes too much effort to make sense of it (though i managed it in the end). Im just gonna learn them

    btw i learnt the ionic equaions so i can apply them to several compounds
    hey man could you explain the priciple of how to work these out as my book doesnt have all the ones i need as apparently any combination of acid and base could come up on my exam ?
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    (Original post by HG1)
    hey man could you explain the priciple of how to work these out as my book doesnt have all the ones i need as apparently any combination of acid and base could come up on my exam ?
    its kinda guesswork but basically in the example of H3PO4:
    PO4^3- is the main ion and its bonded to 3H+ so it's triprotic (Bronsted-Lowry - donates protons). Therefore those H+ will be replaced by 3 positive charges from the metal its reacting with. eg with NaOH:
    H3PO4 + 3Na+ ---> Na3PO4 + 3H+
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    (Original post by Nayzar)
    its kinda guesswork but basically in the example of H3PO4:PO4^3- is the main ion and its bonded to 3H+ so it's triprotic (Bronsted-Lowry - donates protons). Therefore those H+ will be replaced by 3 positive charges from the metal its reacting with. eg with NaOH:
    H3PO4 + 3Na+ ---> Na3PO4 + 3H+
    Thanks alot ! that def makes sense , does it work with all acids and bases though ?
 
 
 
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