The pKa values in water are nitromethane 10.2 and phenol 10.0. The equilibrium constant for CH3NO2 + C6H5O- CH2NO2- + C6H5OH at 298 K is closest to

JEE Advanced levelSingle correct optionDifficulty 3 of 3g2034

The pKa values in water are nitromethane 10.2 and phenol 10.0. The equilibrium constant for $CH X_{3} NO X_{2} + C X_{6} H X_{5} O X^{-} CH X_{2} NO X_{2} X^{-} + C X_{6} H X_{5} OH$ at 298 K is closest to

K = K_{a} (CH X_{3} NO X_{2}) / K_{a} (C X_{6} H X_{5} OH) = 1 0^{- 10.2} /1 0^{- 10.0} = 1 0^{- 0.2} = 0.63

. The reverse value 1.6 results from inverting the ratio, and the others come from using a 2-unit difference.