Answer:
The final and initial concentration of the acid and it's conjugate base are approximately equal, that is we use the weak acid approximation.
Explanation:
The Henderson-Hasselbalch is used to calculate the pH of a buffer solution. It depends on the weak acid approximation.
Since the weak acid ionizes only to a small extent, then we can say that [HA] ≈ [HA]i
Where [HA] = final concentration of the acid and [HA]i = initial concentration of the acid.
It also follows that [A^-] ≈ [A^-]i where [A^-] and[A^-]i refer to final and initial concentrations of the conjugate base hence the answer above.
This is a question similar to one wrestled with by Newton himself, who didn't understand why the planets didn't fall into each other. The reason satellites don't fly into space is because they are being pulled towards the planet by the planet's gravity.
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1. and C.
Terrycot is a fiber that is made by mixing two fibers. Terrycot is a blended fabric made of terylene and cotton. It has better absorbing power as compared to Terylene. Nylon and terylene are produced through condensation polymeriztation.
<em>Hope it helps...</em>