Lead is most likely the best conductor
Yes because it is transparent
0.002389. I believe its that
Answer:
1.Phenolphthalein
2.Method
a.Use the pipette and pipette filler to add 25 cm 3 of alkali to a clean conical flask.
b.Add a few drops of indicator and put the conical flask on a white tile.
c.Fill the burette with acid and note the starting volume.
d.Slowly add the acid from the burette to the alkali in the conical flask, swirling to mix.
Explanation:
Given the following:
Concentration of residual (NH4)+ = 0.12 - 0.03 = 0.09 mol / L
Concentration of created NH3 = 0.03 mol / L
The (NH4) + reacts with all (OH)- to form NH3 and H2O ( Water )
The resultant solution is NH4+ / NH3 buffer system in which (NH4)+ is acid and the NH3 is base or as called the salt.
For a buffer system :
pH = pKa + Log (acid) / (salt)
= 9.25 + Log [ (NH4)+ ] / [ NH3 ]
= 9.25 + Log [ 0.09 ] / [ 0.03 ]
= 9.25 + Log 3
= 9.25 + 0.4771
pH = 9.7271 or 9.73 which is rounded up to 2 decimal places
