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Carefully observe the given figure and u...

Carefully observe the given figure and using data provided find the `EMF` of shown Galvenic cell in volt:

Solution A is `0.1M` each in `NH_(4)OH` and `NH_(4)CI` and solution B is `0.1M` each in `CH_(3)COOH` and `CH_(3)COONa^(+)`.
[Given: `K_(a)(CH_(3)COOH) = 10^(-5), K_(b) (NH_(4)OH) = 10^(-5)` and `(2.303RT)/(F) = 0.06` volt]

Text Solution

Verified by Experts

The correct Answer is:
`0.24`

`pH` of solution (A) : Solution A is a basic Buffer
`pOH = pK_(b) +log.(["Salt"])/([Base]) rArr pOH = 5`
`rArr pH = 9 rArr [H^(+)]_(A) = 10^(-9)M`
`pH` of solution (B): Solution B is Acidic Buffer
`pH = pK_(a) + (["Salt"])/([Base])`
`rArr pH = 5 +log.((0.1))/((0.1)) rArr pH = 5`
`rArr [H^(+)]_(B) = 10^(-5)`
Now, The cell is a concentration cell Cell reaction:
`2H_(B)^(+)(aq) +2e hArr H_(2,B)(g)`
`H_(2,A) (g) hArr 2H_(A)^(+) +2e`
`bar(2H_(B)^(+)(aq)+H_(2,A)(g)overset(n=2)hArr)2H_(A)^(+)(aq)+H_(2,B)(g)`
Nernst Equation for cell
`E_(cell) = 0-(0.06)/(2) log.([H^(+)]_(A)^(2))/([H^(+)]_(B)^(2))`
`=0.06 log ((10^(-4))/(1))rArr +0.24` volt.
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One litre each of a Buffer solution is taken in two beakers connected through a salt bridge. Platinum electrode is immersed in each beaker and electrolysis is carried out for 10,000 sec. using a current of 9.65 Ampere. The Buffer contain (1)/(3) mole each of Na_(2)HPO_(4) and NaH_(2)PO_(4) Initially. using the given data answer the following. Given: ltbr. pK_(a) (H_(3)PO_(4)) = 4, pK_(a) (H_(2)PO_(4)^(-)) = 7 , pK_(a) (HPO_(4)^(2-)) = 10 log 2 = 0.3, log3 = 0.48 2.303 (RT)/(F) = 0.06 at 298K What is the pH of compartment in which oxidation taken place during electrolysis.