Multiple choice Which of the following statements is true? PH3 has higher boiling point than NH3. Nitrogen does not form pentahalide. NH3 is a stronger base than PH3. Both H3PO3 and H3PO4 are tribasic. NH3 acts as Lewis acid. Reveal answer Fill a bubble to check yourself B Correct answer Explanation Due to absence d-orbitals, N cannot extend its valency beyond four. Due to smaller size of nitrogen, there is high electron density on nitrogen.