1. Tardigrade
  2. Question
  3. Chemistry
  4. For the cell Pt | H 2( g )| solution X | KCl (saturated) | Hg 2 Cl 2| Hg mid Pt, the observed EMF at 25° C was 600 mV. When solution X was replaced by a standard phosphate buffer with pH =7.00, the EMF was 718 mV. Find the pH of solution X.

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Q. For the cell $Pt \left| H _{2}( g )\right|$ solution $X \| KCl$ (saturated) $\left| Hg _{2} Cl _{2}\right| Hg \mid Pt$, the observed $EMF$ at $25^{\circ} C$ was $600\, mV$. When solution $X$ was replaced by a standard phosphate buffer with $pH =7.00$, the $EMF$ was $718\, mV$. Find the $pH$ of solution $X$.

Electrochemistry

Solution:

image
subtracting we get
$0.118=0.059 \log \frac{\left[ H ^{+}\right]}{10^{-7}}$
$\Rightarrow \frac{\left[ H ^{+}\right]}{10^{-7}}=100$
$\Rightarrow\left[ H ^{+}\right]=10^{-5}$
$\Rightarrow pH =5$