Which of the following represent the correct order of acidic strength ? (i) HC-=CH gt H_(2)C =CH_(2) gt CH_(3) -CH_(3) (ii) HC-= CH gt CH_(3)-CH_(3) gt H_(2)C=CH_(2) (iii) CH_(3)C-= CH gt HC -= CH gt CH_(3)-C-=C-CH_(3) (iv) HC-= CH gt CH_(3)-C-=CH gt CH_(3)-C-=C-CH_(3)

Which of the following represent the correct order of acidic strength

1.	Which of the following represent the correct order of acidic strength ? (i) HC-=CH gt H_(2)C =CH_(2) gt CH_(3) -CH_(3) (ii) HC-= CH gt CH_(3)-CH_(3) gt H_(2)C=CH_(2) (iii) CH_(3)C-= CH gt HC -= CH gt CH_(3)-C-=C-CH_(3) (iv) HC-= CH gt CH_(3)-C-=CH gt CH_(3)-C-=C-CH_(3)
Answer» I and iii ii and iv I and iv I and iv Solution :Due to the maximum percentage of s CHARACTER (50%), the sp hybridised orbitals of carbon atoms in ethyne molecules have highest ELECTRONEGATIVITY, hence, these attract the shared electron pair of the C-H bond of ethyne to a greater EXTENT than that of the `sp^(2)` hybridised orbitals of carbon in ethene and the `sp^(3)` hybridised orbital of carbon in ethane. Thus in ethyne, HYDROGEN atoms can be liberated as PROTONS more easily as compared to ethene and ethane.