The C–C bond length is maximum in :

What will be the major product when m-cresol is reacted with propargyl bromide (HC$$ \equiv $$C–CH₂Br) in presence of K₂CO₃ in acetone?

The decreasing order of electrical conductivity of the following aqueous solutions is :

0.1 M Formic acid (A),

0.1 M Acetic acid (B),

0.1 M Benzoic acid (C)

Among the following, the energy of 2s orbital is lowest in :