Consider the following Reaction:
HCl(aq) + NaOH(aq) → H2O(1) + NaCl (aq)
The rate of this reaction could be determined by monitoring the change of concentration of :
A. H +
B. Cl -
C. Na +
D. H2O
Hi, I just got this question off line while I was looking for more practice questions for Chemistry 12, and I know the answer but I dont understand the why's and how's of it so can someone please help me out here, the my textbook goes over it but the explanation is very short and doesnt make much sense to me.
Here's another question that's similar (I'll just use 2 ex's just to make sure lol),
Which of the following properties could be used to measure the rate if the following reaction taking place in an open container?
Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2
A. Mass of Zn
B. Solubility of HCl
C. Concentration of Cl-
D. Colour of the solution
Thanks
Answers & Comments
Verified answer
Write the equation out using separated ions:
H^+(aq) + Cl^-(aq) + Na^+(aq) + OH^-(aq) → H2O(ℓ ) + Na^+(aq) + Cl^-(aq)
the conc of Na^+ and Cl^- ions is the same before and after rxn so it is no good monitoring them.
H2O does form and theoretically could could measure the rate of formation of H2O but as it carried out in water ([H2O] = 55.5M) it would be very difficult to determine the increase in [H2O].
[H^+] decreases as the rxn proceeds and is easily measured with a pH meter so this is the answer.
That said the rxn of H^+ and OH^- is essentially instantaneous and so the rate of neutralization cannot be determined only the progress of the rxn as the titration proceeds.
Use the same technique for 2nd ex: the mass of Zn decreases (hint: Zn(s)→Zn^2+(aq); the Zn^2+(aq) is colorless).