The Henderson-Hasselbalch equation can be used to determine the pH of the buffer from the pKa value. The pH of the buffer will be 4.75.
<h3>What is the Henderson-Hasselbalch equation?</h3>
Henderson-Hasselbalch equation is used to determine the value of pH of the buffer with the help of the acid disassociation constant.
Given,
Acid disassociation constant (ka) = 1. 8 10⁻⁵
Concentration of NaOH = 2.0 M
Concentration of CH₃COOH = 2.0 M
pKa value is calculated as,
pKa = -log Ka
pKa = - log (1. 8 x 10⁻⁵)
Substituting the value of pKa in the Henderson-Hasselbalch equation as
pH = - log (1. 8 x 10⁻⁵) + log [2.0] ÷ [2.0]
pH = - log (1. 8 x 10⁻⁵) + log [1]
= 4.745 + 0
= 4.75
Therefore, 4.75 is the pH of the buffer.
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<h3>Answer:</h3>
a) Moles of Caffeine = 1.0 × 10⁻⁴ mol
b) Moles of Ethanol = 4.5 × 10⁻³ mol
<h3>Solution:</h3>
Data Given:
Mass of Caffeine = 20 mg = 0.02 g
M.Mass of Caffeine = 194.19 g.mol⁻¹
Molecules of Ethanol = 2.72 × 10²¹
Calculate Moles of Caffeine as,
Moles = Mass ÷ M.Mass
Putting values,
Moles = 0.02 g ÷ 194.19 g.mol⁻¹
Moles = 1.0 × 10⁻⁴ mol
Calculate Moles of Ethanol as,
As we know one mole of any substance contains 6.022 × 10²³ particles (atoms, ions, molecules or formula units). This number is also called as Avogadro's Number.
The relation between Moles, Number of Particles and Avogadro's Number is given as,
Number of Moles = Number of Molecules ÷ 6.022 × 10²³
Putting values,
Number of Moles = 2.72 × 10²¹ Molecules ÷ 6.022 × 10²³
Number of Moles = 4.5 × 10⁻³ Moles
D i think if not here’s this a collection of beliefs or practices mistakenly regarded as being based on scientific method
