Question

estimation of halogens​

Answer 1

Answer:A known method organic compound is heated it fuming nitric acid in pracence of silver nitrate is hard glass tube is furnace.

Answer 2

Explanation:

Estimation of hologen is done by following two methods

(1) Carius Method (2) Piria & Schiff’s method

1) Carius Method

In this method organic compound containing halogen is heated in a carius tube with F HNO3 in presence of AgNO3, Silver halide (AgX) is precipitated. By Knowing the wt. of silver halide & organic Compound percentage of halogens can be calculated (x=-Cl, -Br,-I)

Calculation –

wt. of organic compound (o.c.) = w gm

wt. of AgCl= x gm

Mol. wt. of AgCl=108+35.5 = 143.5

143.5 gm of AgCl contain Cl = 35.5 gm

x gm of AgCl contain Cl =35.5 x /143.5

w gm of o. c .contains Cl = 35.5 x /143.5

100 gm of o. c .contains Cl =[( 35.5 x) 100 ] / (143.5 w)

% of Cl = (35.5 x wt.of AgCl x 100) /( 143.5 x wt. of o.c.)

General Formula

% of X= (At.wt. of X x wt.of AgX x 100) /( mol.wt. of AgX x wt. of o.c.)

At. wt of Br= 80

Molecular weight of AgBr = 108+80= 188

% of Br =(80 x wt.of AgBr x 100) /( 188 x wt. of o.c.)

Atomic weight of Iodine = 127

Molecular weight of AgI = 108+127=235

% of I= (127 x wt.of AgI x 100) /( 235 x wt. of o.c.)

2) Piria & Schiff’s Method-

Known amount of organic compound is fused with CaO+Na2CO3 in Pt or Ni crucible. The product obtained is dissolved in excess of HNO3 & halogen is precipitated with AgNO3 Soln in the form of AgX. By knowing the wt. of o.c . & AgX, We can calculate the % of halogen.