R$$_f$$ value for 2-methylpropene in a solvent system (Ethyl acetate + ether) is 0.42. 2-methylpropene is treated with dilute H$$_2$$SO$$_4$$ to give major organic product (X). R$$_f$$ value for (X) in the same solvent system under identical condition will be:

Reaction of 2-methylpropene with dilute sulphuric acid gives alcohol by hydration.

Reaction:

$$CH_2=C\left(CH_3\right)_2+H_2O\ +\ dil.\ H_2SO_4\longrightarrow\ \left(CH_3\right)COH$$

Major Product Formed:

X= tert-butyl alcohol(2-methylpropan-2-ol)

In TLC:

$$R_f=\frac{\text{Distance travelled by compound}}{\text{Distance travelled by solvent}}$$

More polar compounds interact more strongly with polar stationary phase and therefore move less.

Hence:

More polar compound $$=>$$Lower $$R_f$$ value

2-methylpropene is non-polar.

tert-butyl alcohol contains: $$-OH$$ group and is more polar.

Therefore, product X will have lower $$R_f$$​ value than 0.42.

Hence,

$$R_f\text{ value of }X<0.42$$

Therefore, Option D is correct