Recall that at the equivalence point of a titration:
Also, recall that:
For alkali metal (Group 1A) hydroxide → There is 1 OH–
Solving for MMbase:
= 102.6 g/mol
Molar mass of metal hydroxide = molar mass of metal + molar mass O + molar mass H
A 4.36-g sample of an unknown alkali metal hydroxide is dissolved in 100.0 mL of water. An acid-base indicator is added and the resulting solution is titrated with 2.50 M HCl (aq)solution. The indicator changes color signaling that the equivalence point has been reached after 17.0 mL of the hydrochloric acid solution has been added.
What is the identity of the alkali metal cation: Li+, Na+, K+, Rb+, or Cs+?
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What scientific concept do you need to know in order to solve this problem?
Our tutors have indicated that to solve this problem you will need to apply the Equivalence Point concept. If you need more Equivalence Point practice, you can also practice Equivalence Point practice problems.