Ascientist wanted to test the relationship between pressure, force, and area to confirm that pressure equals force/area. he discovered that if the area was increased during the experiment, the pressure decreased. assume that many trials were conducted and the force was kept constant. based on the experiment, what relationship exists between area and pressure

Pressure is indirectly related to area.

Explanation:

The change in pH is 0.04.

Further explanation

Given:

0.50 L of a buffer solution containing 0.15 M in HF and 0.20 M in NaF.The Ka for HF is 3.5 x 10⁻⁴.

Question:

Calculate the change in pH when 2.0 x 10⁻² mol of NaOH is added to this buffer?

The Process:

Step-1

Let us prepare all the moles of substances.

 

Moles of HF =  

Moles of NaF =  

Moles of NaOH =

Step-2

Let use the ICE table (in mol).

                       

Initial:             0.075     0.02         0.10        -

Change:         0.02       0.02         0.02    0.02

Equlibrium:    0.055       -             0.08    0.02

NaOH as a strong base acts as a limiting reagent. The remaining HF as a weak acid and NaF salt forms an acidic buffer system.The NaF salt has valence = 1 according to the number of F⁻ ions as a weak part, i.e.,  HF and F⁻ are conjugate acid-base pairs.

Step-3

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

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.

Thus, the buffer pH due to addition of NaOH is equal to 3.62.

Step-4

Let us calculate the buffer pH value before the addition of NaOH.

Moles of HF =  0.075 moles

Moles of NaF = 0.10 mmol

Thus, the initial pH of this buffer is 3.58. This proves the nature of the buffer that keeps the pH value relatively unchanged with the addition of a strong electrolyte.

Finally, we calculate the change in pH.

Learn moreThe similar problem The ratio of HCO₃⁻ to H₂CO₃ in an exhausted marathon runner whose blood pH is 7.2 Calculate the pH of an acidic buffer system