Question

SYSTEM 1: ACID/BASEEQUILIBRIA

o Place 10 drops of 0.5M K2CrO4 to a clean test tube.
o Add 10 drops of concentrated HCl. Observe the change ofcolor.
o And then add 5 drops of 6N NaOH. Record your observations.

Equilibrium System:
2- + 2-
2CrO + 2H (aq) --> Cr O + H O (l)
4 2 7 2

+Expected results for system1?

2. SYSTEM 2: EQUILIBRIA OFACID/BASE INDICATORS

o Place 2 drops of methyl violet to a clean test tube. Add 20 mL ofdistilled water, mix well.
Divide the solution evenly into two test tubes. Save one as areference. Note the color.
o Test tube #1 (reference): add nothing
o Test tube #2:
 Addition #1: add the 6M HCl solution drop wise until furtheraddition results in no significant change. Observe thechange.
 Addition #2: add the 6M NaOH solution drop wise until furtheraddition results in no color change. Observe the change.
 Addition #3: again add the 6M HCl solution drop wise untilfurther addition results in no significant change. Observe thechange.

Equilibrium System:
+ _
H(MV)(aq) + H O(l) --> H O (aq) + MV (aq)
2 3

+Expected results for system2?