Explain i. It is advisable to grow a leguminous crop on a soil every three or four years

Explanation

i.Leguminous plánts have nodules in their roots. Nodules have nitrogen- fixing bacteria. and thus eonvert .N_2. of soil to soluble nitrates, the soil thus becomes nitrogen deficient after two or three years.
ii. Bromine has larger size than chinrine hence unable to form .mid PBr_h^prime. ion. .PBr_5. exists as ..[PBr_4rfloor^* mid B rrfloor.
P can accommodate .6 Cl^-. ions. Hence .[RCl_6]. - is known.