See image — AITS & Test Series Chemistry Question

💡 Solution & Explanation

Initial moles of H2O2 = 2 × 2 = 4 Moles of H2O2 left after 20 min. = 4 × 2 1 2 = 1 (2 half lives) Moles of H2O2 decomposed 20 min. = 4 – 1 = 3 H2O2  H2O + 1 2 O2 Moles of O2 formed during 20 min. = 3/2 Volume change = 3 R T 2 P   q = 0; U = W W = –Pext (V2 – V1) = – Pext V = – 3 2 × 2 × 300 = – 900 Cal.