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Among the following acids which has the lowest pK_{a} value?

  • Option 1)

    CH_{3}COOH

  • Option 2)

    \left ( CH_{3} \right )_{2}CH-COOH

  • Option 3)

    HCOOH

  • Option 4)

    CH_{3}CH_{2}COOH

 

Answers (1)

best_answer

As we learnt in 

Value of Ka -

K_{a}=\frac{[H^{+}]\:[\bar{X}]}{[HX]}


P(K_{a})=-log(K_{a})

- wherein

At a given temperature T,  Ka is a measure of the strength of the acid  HX. Ka  is dimensionless quantity.

 

 

Higher the pK_{a} value, weaker is the acid. Hence, stronger acid has lower pK_{a}  value.

In given options, HCOOH is the strongest acid.


Option 1)

CH_{3}COOH

This option is incorrect

Option 2)

\left ( CH_{3} \right )_{2}CH-COOH

This option is incorrect

Option 3)

HCOOH

This option is the correct

Option 4)

CH_{3}CH_{2}COOH

This option is incorrect

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Plabita

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