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Equilibrium

Question
CBSEENCH11008361
Wired Faculty App

What is [H+] in mol/L of a solution that is 0.20 M in CH3COONa and 0.10 M in CH3COOH? 
(Ka for CH3COOH = 1.8 x 10-5 )

  • 3.5 x 10-4

  • 1.1 x 10-5

  • 1.8 x 10-5

  • 9.0 x 10-6

Solution

D.

9.0 x 10-6

CH3COOH (weaK acid) and CH3COONa (conjugated salt) form acidic buffer and for acidic buffer,
pH space equals space pK subscript straight a space plus space log space fraction numerator open square brackets salt close square brackets over denominator left square bracket acid right square bracket end fraction and left square bracket straight H to the power of plus right square bracket space equals space minus space antilog space pH pH space equals space minus space log space straight K subscript straight a space plus space log space fraction numerator left square bracket salt right square bracket over denominator left square bracket acid right square bracket end fraction space space space space space left square bracket therefore space pK subscript straight a space equals space minus space log space straight K subscript straight a right square bracket space equals space minus log space left parenthesis 1.8 space straight x space 10 to the power of negative 5 end exponent right parenthesis space plus space log space fraction numerator 0.20 over denominator 0.10 end fraction equals space 4.74 space plus space log space 2 equals space 4.74 space plus space 0.3010 space equals space 5.041 Now comma space left square bracket straight H to the power of plus right square bracket space equals antilog space left parenthesis negative 5.045 right parenthesis equals space 9.0 space straight x space 10 to the power of negative 6 end exponent space mol divided by straight L

Some More Questions From Equilibrium Chapter

Give two examples of physical equilibrium.

What kind of molecules in a liquid can evaporate?

Name the factors on which vapour pressure of any liquid depends.

Which measurable property becomes constant in water vapour equilibrium?

Give an example from daily life in which there is gas solution equilibrium?

A crystal of common salt of a given mass is kept in its aqueous solution. After 24 hours, its mass remains the same. Is the crystal in equilibrium with the solution?

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