A NaI HI B KBr HBr C RbCl HCl D CsF HF E none of the above 9 Adding Strong

A nai hi b kbr hbr c rbcl hcl d csf hf e none of the

This preview shows page 5 - 11 out of 30 pages.

A) NaI, HI B) KBr, HBr C) RbCl, HCl D) CsF, HF E) none of the above 9 Adding Strong Acids or Bases to a Buffer Buffer Purpose: resist drastic changes in pH when limited amounts of strong acid or base is added A. If Acid is added , H + ) ( ) ( ) ( aq A aq H aq HA (Weak Acid) (Conjugate Base) For a buffer : H + reacts with in buffer creating more A - HA H + (aq) + A- (aq) HA (aq) B . If Base added , OH - OH - reacts with in buffer creating more HA A - OH - (aq) + HA (aq) A - (aq) + H 2 O (l) 10
Image of page 5
Adding Strong Acids or Bases to a Buffer Added acid or base reacts with something in the buffer ( reactions go to completion) Added acid or base is limiting (they are consumed completely) For the Buffer: ) ( ) ( ) ( aq A aq H aq HA (Weak Acid) (Conjugate Base) 11 Adding Strong Acids or Bases to a Buffer To calculate pH: 1. Write the neutralization reaction for substance added to buffer 3. Use a ICE table (must be in MOLES ) 2. Use Henderson Hasselbalch equation (must be in Molarity ) 12 It’s limiting If strong acid or base added, it’s completely consumed
Image of page 6
Example A 1.50L solution contains 0.100M HCOOH M and 0.150 HCOONa. Calculate the pH when 10.0mL of 5.00M NaOH is added. 13 Example A 1.50L solution contains 0.100M HCOOHM and 0.150 HCOONa. Calculate the pH when 10.0mL of 5.00M HCl is added. 14
Image of page 7