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JEE Advanced levelOne or more correct optionsDifficulty 3 of 3g2038

Use pKa values in water: pentane-2,4-dione 9.0, nitromethane 10.2, propanone 19.3, ethanenitrile 25. Which statements are correct?

AKa of pentane-2,4-dione is more than $1 0^{10}$ times that of propanone.
BNitromethane is a stronger acid than pentane-2,4-dione.
CKa of propanone is more than $1 0^{5}$ times that of ethanenitrile.
DKa of nitromethane is about $1 0^{5}$ times that of propanone.

Answer: A, C

Ka ratios: pentane-2,4-dione/propanone =

1 0^{10.3} = 2.0 e + 10

(true). Nitromethane (10.2) is weaker than pentane-2,4-dione (9.0) by a factor of 16, so statement 2 is false. Propanone/ethanenitrile =

1 0^{5.7} = 5.0 e + 05

(true). Nitromethane/propanone =

1 0^{9.1}

, not

1 0^{5}

, so statement 4 is false.

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