ph control Flashcards
Name two applications that utilize pH control:
Completeness of precipitation
Rate of settling
car manufacturing
answer A,B
Explain why pH is hard to control with “standard” process control strategies.
because it don’t move the same. Small amounts of acid can make a big change around PH 9 to 5 but if your at PH 13 you can put a lot of acid and nothing would change much.
What determines whether an acid is considered a strong or a weak acid?
A strong acid fumes when exposed to air and a weak acid doesn’t
A strong acid ionizes almost completely and a weak acid ionizes only slightly
answer B
What type of signal is produced by a pH electrode?
Milli volt
ohms
answer A
On the pH scale, a higher number means more acidic.
true
false
answer false
A solution with pH=5 has 10 times more H+ concentration than a solution with pH=6
true
false
answer true
If you were neutralizing a strong base with a strong acid, which setpoint would be most difficult to control?
PH 4
PH 7
answer B
If an analytical controller is adding an acid to control pH and the pH reads above setpoint, what will the controller do with the acid control valve?
Open the acid valve more
Back-calculate the acid valve position
answer A
In an adaptive gain controller controlling pH at 7,
The gain would increase as the pH deviated from setpoint
The gain would remain constant as the pH deviated from setpoint
answer A
