Methyl orange is an indicator with a K_a of 1 × 10^-4. Its acid form, HIn, is red, while its base form, In^-, is yellow. At pH 6.0, the indicator will be A) yellow. B) orange. C) red. D) blue. E) not enough information

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Quizplus · Accepted Answer

Methyl orange changes color around its pKa, which is 4 (since pKa = -log(Ka)). At pH 6.0, which is higher than the pKa, the solution will be in the basic form, In⁻, which is yellow.

Methyl Orange Is an Indicator with a Ka of 1

Methyl Orange Is an Indicator with a K_a of 1