Phosphorus occurs in nature in the form of stable phosphates. (Animal bones also contain calcuim phosphate (58%)).The important minerals are: (i)Phosphorite, Ca_3(PO_4)_2(ii)Chloraptite,Ca_3(PO_4)_2CaCl_2 (iii)Fluoraptite, Ca_3(PO_4)_2CaF_2 There are some depoists of nitrates and phosphates in earth's crust.Nitrates are more soluble in water Nitrates are difficult to reduce under the laboratory conditions but microbes do it easily.Compounds of phosphorus and nitrogen are used as fertilizer. Amongs the following select the correct statement :

Phosphorus occurs in nature in the form of stable phosphates. (Animal

1.	Phosphorus occurs in nature in the form of stable phosphates. (Animal bones also contain calcuim phosphate (58%)).The important minerals are: (i)Phosphorite, Ca_3(PO_4)_2(ii)Chloraptite,Ca_3(PO_4)_2CaCl_2 (iii)Fluoraptite, Ca_3(PO_4)_2CaF_2 There are some depoists of nitrates and phosphates in earth's crust.Nitrates are more soluble in water Nitrates are difficult to reduce under the laboratory conditions but microbes do it easily.Compounds of phosphorus and nitrogen are used as fertilizer. Amongs the following select the correct statement :
Answer» Regular use of Superphosphate of lime fertilizers increases the acidity of soil `Ca_3(PO_4)_2CaF_2+H_3PO_4 to Ca(H_2PO_4)_2+2HF` Here instead of `H_2SO_4, H_3PO_4` is used to avoid the formation of solution `CaSO_4` between nitrates and phosphates, nitrates are more abundant in earth crust Polyphosphates are used as water SOFTENING agents because they form soluble complexes with CATIONIC SPECIES Solution :`H_3PO_4` is used to avoid the formation of the insoluble `CaSO_4`(WASTE product) Polyphosphate SEPARATE `Ca^(2+)` and `Mg^(2+)` (present in hard water ) and forms soluble complex with `Ca^(2+)` and `Mg^(2+)` which do not precipitate with `CO_3^(2-)` and soap.