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