To calculate the pH of this solution, we use the
Henderson-Hasselbalch equation:
pH = pKa + log ([A-]/[HA])
Where,
[A-] = Molarity of the conjugate base =
CH3COO- = 0.29 M<span>
<span>[HA] = Molarity of the weak acid = CH3COOH = 0.18 M</span></span>
pKa = dissociation constant of the weak acid =
4.75
When KOH is added to the buffer, the chemical
reaction is:
CH3COOH + KOH = CH3COO-K+ + H2O
Therefore when 0.0090 mol KOH is added, 0.0090
mol acid is neutralized, and 0.0090 mol CH3COO- is produced.
[CH3COO-] = [0.0090 mol + 0.375 L (0.29 mol/L) ]
/ 0.375 L = 0.314 M
[CH3COOH] = [-0.0090 mol + 0.375 L (0.18 mol/L) ]
/ 0.375 L = 0.156 M
Going back to Henderson-Hasselbalch
equation:
pH = 4.75 + log (0.314 / 0.156)
<span>pH = 5.054</span>
The significance of melting points are
- it gives us a idea about inter molecular force which binds the particles together.
- at melting point the solid and liquid states exist in equilibrium.
<h3>What is melting point?</h3>
The melting point is the temperature at which a given substance change its physical state from solid to liquid. At this point solids and liquids exist at equilibrium. Melting point of a substance depends on pressure. The melting point of ice increases when pressure decreases. Melting point of a substance decreases by the presence of impurities in it. so you increase or decrease the melting point on any substance by adding more impurities. Ionic bonds, shape and size of molecules are some other factors that affect the melting point.
To learn more about melting point refer:
brainly.com/question/25689052
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