Identify false statement about transition elements.

Which among the following is not haloalkyne?

Which isomer of $\mathrm{C}_4 \mathrm{H}_9 \mathrm{OH}$ has highest boiling point?

A buffer solution contains equal concentrations of weak acid and its salt with strong base. Calculate pH of buffer solution if dissociation constant of weak acid is $1.8 \times 10^{-5}$.