Acids are donors of protons (H+) and bases are acceptors of protons.
For example:
1) hydrochloric acid (HCl) in reaction with water give one proton to water and become chloride anion (Cl-).
2) ammonia (NH3) Is base, in reaction with water accepts one protone and become ammonium cation (NH4+).
Answer:
1. an educated guess
2. data
3. what changes in experiment
4. what stays the same in both groups
5. the group where nothing changes, normal
6. group with independent variable, what's being tested
Henderson–Hasselbalch equation is given as,
pH = pKa + log [A⁻] / [HA]
-------- (1)
Solution:
Convert Ka into pKa,
pKa = -log Ka
pKa = -log 1.37 × 10⁻⁴
pKa = 3.863
Putting value of pKa and pH in eq.1,
4.29 = 3.863 + log [lactate] / [lactic acid]
Or,
log [lactate] / [lactic acid] = 4.29 - 3.863
log [lactate] / [lactic acid] = 0.427
Taking Anti log,
[lactate] / [lactic acid]
= 2.673
Result:
2.673 M
lactate salt when mixed with 1 M Lactic acid produces a buffer of pH = 4.29.
The cell notation is:
![Mg(s)|Mg^{+2}(aq)||Ag^{+}(aq)|Ag(s)](https://tex.z-dn.net/?f=Mg%28s%29%7CMg%5E%7B%2B2%7D%28aq%29%7C%7CAg%5E%7B%2B%7D%28aq%29%7CAg%28s%29)
here in cell notation the left side represent the anodic half cell where right side represents the cathodic half cell
in anodic half cell : oxidation takes place [loss of electrons]
in cathodic half cell: reduction takes place [gain of electrons]
1) this is a galvanic cell
2) the standard potential of cell will be obtained by subtracting the standard reduction potential of anode from cathode
![E^{0}_{Mg}=-2.38V](https://tex.z-dn.net/?f=E%5E%7B0%7D_%7BMg%7D%3D-2.38V)
![E^{0}_{Ag}=+0.80V](https://tex.z-dn.net/?f=E%5E%7B0%7D_%7BAg%7D%3D%2B0.80V)
Therefore
![E^{0}_{cell}=0.80-(-2.38)=+3.18V](https://tex.z-dn.net/?f=E%5E%7B0%7D_%7Bcell%7D%3D0.80-%28-2.38%29%3D%2B3.18V)
3) as the value of emf is positive the reaction will be spontaneous as the free energy change of reaction will be negative
Δ![G^{0}=-nFE^{0}](https://tex.z-dn.net/?f=G%5E%7B0%7D%3D-nFE%5E%7B0%7D)
As reaction is spontaneous and there will be conversion of chemical energy to electrical energy it is a galvanic cell.