GROUP 15 ELEMENT QUES . 

1) An unknown salt X react with hot conc. straight H subscript 2 SO subscript 4 to produce a brown coloured gass which intensifies on addition on copper turnings . on adding dilute ferrous sulphate olution to an aqueous solution to an aquaeous solution of X and then carefully adding conc. straight H subscript 2 SO subscript 4 along the sides of testtube , a brown complex Y i formed at the interface between the solution and straight H subscript 2 SO subscript 4 . identify X and Y and write the reactions involved . 

2) A transuclent waxy solid A on heating it on inert atmosphere is converted into its allotropic form B . Allotrope A on reaction with very dilute aqueous NaOH LIBERATES a highly poisonous gas C having rotten fih mell . The ubstance A reacts with excess of chlorine to form D which hydrolysis to form compound E .Identify A to E . Also write the reaction involved 

 Thankyou

Asked by niharikapabba2605 | 7th Aug, 2018, 01:00: AM

Expert Answer:

1) X = NO3- salt  and Y = [Fe(H2O)5(NO)]2+
Reactions:
 
 NO3- + 3Fe2+ +4H+ → NO + 3Fe3+ + 2H2O
 
[Fe(H2O)6]2+ + NO → [Fe(H2O)5(NO)]2+ + H2O
                                 Brown complex
 
2) The solid A is white waxy and highly reactive phosphorous P4 
 
On heating at 573 K to white phosphorous, it converts into red phosphorous compound B.
 
And on heating with alkalies like KOH white phosphorous forms potassium hypophosphite and PH3 which is poisonous, colorless with the rotten fish smell is the compound C.
P subscript 4 space plus space 3 K O H space plus 3 H subscript 2 O space rightwards arrow with blank on top space P H subscript 3 space plus space 3 K H subscript 2 P O subscript 2
 
White phosphorus reacts with the excess of dry chlorine to form phosphorous pentachloride PCl5 is compound D
P subscript 4 space plus space 10 C l subscript 2 space rightwards arrow with blank on top space 4 P C l subscript 5
phosphorous pentachloride PCl5 is hydrolyzed by moist air to form POCl3 which reacts further with water to form phosphoric acid H3PO4 compound E
PCl subscript 5 space plus space straight H subscript 2 straight O rightwards arrow with blank on top space POCl subscript 3 space plus space 2 HCl
POCl subscript 3 space plus space straight H subscript 2 straight O space rightwards arrow with blank on top space straight H subscript 3 PO subscript 4 space plus space 3 HCl

Answered by Ramandeep | 7th Aug, 2018, 03:32: PM