In which of the following acids is a P–P bond present?

CHEMISTRY · Single correct

Problem

In which of the following acids is a P–P bond present? (1) Tetrapolyphosphoric acid,

\mathrm{H}_6\mathrm{P}_4\mathrm{O}_{13}

(2) Pyrophosphoric acid,

\mathrm{H}_4\mathrm{P}_2\mathrm{O}_7

(3) Hypophosphoric acid,

\mathrm{H}_4\mathrm{P}_2\mathrm{O}_6

(4) Polymetaphosphoric acid,

(\mathrm{HPO}_3)_n