Question

[URGENT!] - Acids and Bases

a) What is the pH of a solution in which 25.0 ml of a 0.400 M solution of HCl is added to 75.0 ml of a 0.500 M solution of ammonium hydroxide?

b) If 0.050 moles of KOH were added to the buffer solution, what would be the resulting pH?

c) Explain what chemical reaction(s) happen as KOH is added to the buffer solution.

Answer 1

b) answer. NaOH is a strong base, meaning it will dissociate basically completely in solution to form

N

a

+

and

O

H

−

ions in solution.

One mole of

O

H

−

ions is created for every mole of NaOH that is dissolved. If it's a .05 M solution of NaOH, then it can also be interpreted to be a .05M solution of

OH−.pOH

(The pH scale for bases) can be found by taking the negative logarithm of OH− concentration.

pOH = −log

[05M] = 1.3.

However, we are trying to find

pH

, so we must use the formula pOH+pH

=14 .Now that we know pOH

=1.3pH=14−1.3=12.7

.