A buffer is prepared by adding 9.00g of ammonium chloride (NH 4 Cl) to 250mL of

Question

A buffer is prepared by adding 9.00g   of ammonium chloride (NH 4 Cl)  to 250mL   of 1.00 M   NH 3   solution.

Part A   I got this.  The PH of the buffer = 9.32

Part B Write the complete ionic equation for the reaction that occurs when a few drops of nitric acid are added to the buffer

.Express your answer as a chemical equation. Identify all of the phases in your answer.

Part C Write the complete ionic equation for the reaction that occurs when a few drops of potassium hydroxide solution are added to the buffer.Express your answer as a chemical equation. Identify all of the phases in your answer.

Only need help with B and C.   I entered them both but it keeps saying I'm formatting it wrong.  HELP

Explanation / Answer

We'll use the Henderson Hasselbalch equation pH=pKa + log([base]/[acid])

pKa = -log[Ka] = 9.25

NH3: (9.00 g / 17 g/mol) / 2.5 L = 0.212 M
NH4Cl: (24.0 g / 53.45 g/mol) / 2.5 L = 0.180 M

So pH = 9.25 + log(0.212/0.180)
= 9.25 + 0.0711
= 9.32

2. NH4+ + Cl- + NH3 + HNO3 <==> 2NH4+ + Cl- + NO3-

3. NH4+ + Cl- + NH3 + KOH <==> 2NH3+ + Cl- + H2O + K+

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