Question

The number of acidic hydrogen atoms in 1- butyne and 2- butyne is _______ respectively.

• A. 1, 0
• B. 0, 1
• C. 1, 1
• D. 1, 2

Answer 1

The correct option is A 1, 0

According to the structure, the carbon numbered as 1, in, 1-butyne has hydrogen attached to it. This carbon atom is ‘sp’ hybridized, which means it has a higher s character that means higher electronegativity, therefore, the tendency to donate the H+ ion will be higher in 1-butyne.

Hence i-butyne has one 1 acidic hydrogen.

And in 2-butyne, both the carbons involved in triple bonding do not have a hydrogen atom, and the terminal carbon atoms are ‘sp3’ hybridized, meaningless ‘s’ character in them, therefore the tendency to donate H+ ion will be less.

Hence 2-butyne has 0 acidic hydrogens.

Hence, 1-butyne is more acidic than 2-butyne.