Chemistry, 04.07.2019 11:00 rntaran2002

Abuffer solution is made by dissolving 0.45 moles of a weak acid (ha) and 0.33 moles of koh into 710 ml of solution. what is the ph of this buffer? ka = 6x10-6 for ha.

Answers: 1

Show answers

Answers

Answer from: jasminethomas5159

The pH of the buffer solution is 5.08.

Solution:

$K_a\text{of the acid HA}=6\times 10^{-6}$

Volume of buffer solution=710 mL = 0.710 L (1L=1000ml)

$[concentration]=\frac{\text{number of moles}}{\text{volume in litres}}$

$[HA]=\frac{0.45}{0.710} mol/L,[KOH]=\frac{0.33}{0.710} mol/L$

ph of the buffer can be calculated by using buffer equation:

$pH=pK_a+log\frac{[base]}{[acid]}$ ...(1)

On substituting values in (1) we get

$pH=-log(6\times 10^{-6})+log\frac{\frac{0.33}{0.710}}{\frac{0.45}{0.710}}=5.08$

The pH of the buffer solution is 5.08.

Answer from: danyratilladc

5.66

Further explanation

Given:

0.45 moles of a weak acid (HA) and 0.33 moles of KOHA buffer solution is made by dissolving a weak acid (HA) and KOH into 710 mL of solution. $\boxed{ \ K_a = 6 \times 10^{-6} \ for \ HA \ }$

Question:

What is the pH of this buffer?

The Process:

The balanced equation for this reaction is:

$\boxed{ \ HA + KOH \rightarrow KA + H_2O \ }$

Initial: 0.45 0.33 - -

Change: 0.33 0.33 0.33 0.33

Final: 0.12 - 0.33 0.33

(excess) (limiting)

When 0.45 moles of HA react with 0.33 moles of KOH, 0.33 moles of KA are produced, and 0.12 moles of HA remain unreacted.

At the end of the above reaction, the buffer solution (or buffer system) is composed of weak acids mixed with their conjugate base salts.

To calculate the specific pH of a given buffer, we need using The Henderson-Hasselbalch equation for acidic buffers:

$\boxed{ \ pH = pKa + log_{10} \frac{[A-]}{[HA]} \ }$

where,

Ka represents the dissociation constant for the weak acid; [A-] represent the concentration of the conjugate base (i.e. salt); [HA] is the concentration of the weak acid.

Let us prepare the concentrations.

$\boxed{ \ [HA] = \frac{0.12 \ moles}{0.710 \ L} = 0.169 \ M \ }$

From KA salt ionization: $\boxed{ \ KA \rightarrow K^+ + A^-\ }$ we observe that there is one A⁻ ion or the valence is 1.

Hence, $\boxed{ \ [A^-] = [KA] \times valence \ }$ , so

$\boxed{ \ [A^-] = \frac{0.33 \ moles}{0.710 \ L} \times 1 = 0.465 \ M \ }$

Let us calculate the pH of this buffer.

$\boxed{ \ pH = -log(6 \times 10^{-6}) + log \Big( \frac{0.465}{0.169} \Big) \ }$

Recall this: $\boxed{ \ - log(a \times 10^b) \rightleftharpoons b - log \ a \ }$

$\boxed{ \ pH = 6 - log 6 + log \Big( \frac{0.465}{0.169} \Big) \ }$

Thus, the pH of this buffer is 5.66 and represents an acidic buffer solution.

_ _ _ _ _ _ _ _ _ _

Notes:

A buffer solution is one that naturally resists changes in pH when lesser quantities of an acid or an alkali are carefully added to it.

Acidic buffer solutions. An acidic buffer solution is simply one which has a pH of less than 7. Acidic buffer solutions are commonly gained from a weak acid and one of its salts. Alkaline buffer solutions. An alkaline buffer solution has a pH greater than 7. Alkaline buffer solutions are commonly gained from a weak base and one of its salts. Learn moreCalculating the pH value of weak base How much of these solutions he needs to drain and replace with 70% acid solution to obtain 100g of 60% acid solution What is the concentration of a solution formed by diluting 25.0 ml of a 3.2 M NaCl solution to 135.0 ml?
Abuffer solution is made by dissolving 0.45 moles of a weak acid (ha) and 0.33 moles of koh into 710

Abuffer solution is made by dissolving 0.45 moles of a weak acid (ha) and 0.33 moles of koh into 710

Answer from: Quest

The real answer is keeping the world healthy so we won’t die

Answer from: Quest

what are the statements

Another question on Chemistry

Chemistry, 22.06.2019 04:50

Acompound contains c, h, and o atoms. when 1.130 g of the compound is burned in oxygen, 1.064 g co2 and 0.3631 g h2o are produced. what is the empirical formula of this compound?

Answers: 1

Answer

Chemistry, 22.06.2019 05:30

According to periodic trend, which of the following most likely has the highest ionization energy? kr be ni sc

Answers: 3

Answer

Chemistry, 22.06.2019 14:30

For the reaction shown, find the limiting reactant for each of the following initial amounts of reactants. 4al(s)+3o2(g)→2al2o3(s) a) 1 molal, 1 mol o2 b) 4 molal, 2.6 mol o2 c) 16 molal, 13 mol o2 d) 7.4 molal, 6.5 mol o2

Answers: 3

Answer

Chemistry, 22.06.2019 16:30

How do i turn 2 s into one in the products

Answers: 1

Answer

You know the right answer?

Abuffer solution is made by dissolving 0.45 moles of a weak acid (ha) and 0.33 moles of koh into 710...

Questions