Return to Blog Homepage

MCAT Chemistry Question — Acid/Base Pairs

  • by John
  • Jan 09, 2014
  • MCAT Blog, MCAT Question of the Day

Which of the following acid/base pairs yields the most nearly neutral aqueous solution when mixed?

a) HCl/NaF

 b) H2CO3/2 NaOH

c) HCl/NaOH

d) HBr/NH3

 

Explanation:

 

a) incorrect, strong acid + weak base forms NaCl and HF, the HF hydrolyzes to H3O+ and F, pH<7

b) incorrect, weak acid + strong base forms Na2CO3 + 2 H2O, and the CO32- ion autoionizes water, to create OH–  ions, pH>7

c) correct, strong acid + strong base forms NaCl + H2O and salt ions do not react with water to change pH, pH=7

d) incorrect, strong acid + weak base forms NH4Br, the NH4+ ions weakly dissociates to NH3 + H+ and Br does not react with water, pH<7

 

 

 

Want more MCAT practice?

We’ve got options for every schedule and learning style!

From the best online MCAT course created by top instructors with 524+ MCAT scores to the most representative full-length practice exams and private tutoring, we can custom tailor your MCAT prep to your goals!

Not sure which option is right for you? Schedule a free MCAT consultation with an MCAT Advisor using the form below. No obligation, just expert advice.

Schedule My Free Consultation

Submit a Comment