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68538 Chemistry, Other
What is the final solution pH after 60 mL 0.05 M Ba(OH)₂ is mixed with 25 mL 0.20 M HNO₃?
Answer:
Ba(OH)2+2HNO3=Ba(NO3)2+2H2OBa(OH)2 is a strong alkali. HNO3 is a strong acid.
In order to determine pH, we have to determine limiting reagent.
According to equation, n(Ba(OH)2)=2⋅n(HNO3)
CM=n/Vn=CM⋅Vn(Ba(OH)2)=0.05⋅60=3 mmoln(HNO3)=0.2⋅25=5 mmolBut it must be: 2⋅n(Ba(OH)2)=3⋅2=6 mmol
Therefore, HNO3 is the limiting reagent. There will be an excess of Ba(OH)2 of (3−5/2=0.5 mmol) with an anticipated basic pH.
pOH=−lg[0.0005]=3.3pH+pOH=14pH=14−3.3=10.7