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Neutralisation reaction?

Hey guys,
I've got this question on a chem past paper:

Which equation is not a neutralisation reaction?
A - Ca(s) + 2HCl(aq) --> CaCl2(aq) + H2(g)
B - H+(aq) + OH-(aq) --> H2O(l)
C - K2CO3(aq) + 2HNO3(aq) --> 2KNO3(aq) + H2O(l) + CO2(g)
D - NH3(aq) + HCl(aq) --> NH4Cl(aq)

Apparently the answer's A, but I can't see why?
Thanks :smile:
Original post by arosen
Hey guys,
I've got this question on a chem past paper:

Which equation is not a neutralisation reaction?
A - Ca(s) + 2HCl(aq) --> CaCl2(aq) + H2(g)
B - H+(aq) + OH-(aq) --> H2O(l)
C - K2CO3(aq) + 2HNO3(aq) --> 2KNO3(aq) + H2O(l) + CO2(g)
D - NH3(aq) + HCl(aq) --> NH4Cl(aq)

Apparently the answer's A, but I can't see why?
Thanks :smile:


A neutralisation reaction is the reaction between an acid and a base to produce a salt, and depending on the conditions, one mole of water.

As much as no water is produced in D, it's still a neutralisation reaction in the sense that it agrees with Brønsted-Lowry acid-base rules: NH3 accepts a proton from HCl to become NH4+, and then the Cl- ion will form an ionic salt (NH4Cl) with NH4+.

A is a redox reaction, not a neutralisation reaction. This is because calcium's oxidation state goes from 0 to +2 (from Ca to CaCl2), whereas hydrogen's oxidation number goes from +1 to 0 (from HCl to H2). Not only that, but calcium isn't acting as a base as it's not accepting any protons, hence every reaction apart from A is a neutralisation reaction.
(edited 5 years ago)
A neutralisation reaction produces water from the protons from the acid and the hydroxides from the base (or if it’s ammonia it doesn’t produce water but is still neutralisation)
Reply 3
Original post by Kian Stevens
A neutralisation reaction is the reaction between an acid and a base to produce one mole of salt, and depending on the conditions, one mole of water.

As much as no water is produced in D, it's still a neutralisation reaction in the sense that it agrees with Brønsted-Lowry acid-base rules: NH3 accepts a proton from HCl to become NH4+, and then the Cl- ion will form an ionic salt (NH4Cl) with NH4+.

A is a redox reaction, not a neutralisation reaction. This is because calcium's oxidation state goes from 0 to +2 (in Ca to CaCl2), whereas hydrogen's oxidation number goes from +1 to 0 (in HCl to H2). Not only that, but calcium isn't acting as a base as it's not accepting any protons, hence every reaction apart from A is a neutralisation reaction.


thank you so much! :h:

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