Test method for mixed catalyst solution of cobalt acetate, manganese acetate and hydrobromic acid (3)

3.

3.

Accurately add excess silver nitrate standard titration solution to the sample solution

Reaction mechanism:

AgN03 _.

AgNO ₃ +KSCN→AgSCN↓+KNO ₃

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Bromine (Br ^- ) content mass fraction W ₃ , values are expressed in%, according to equation (3) is calculated:

Where:

V ₁ —The value of the volume of the silver nitrate standard titration solution (3.
6.
2.
4) added, in milliliters (mL) (V1=20);

V ₂ —The value of the volume of the potassium thiocyanate standard titration solution (3.
6.
2.
4) consumed by the sample, in milliliters (mL);

c ₁ —The exact value of the concentration of silver nitrate standard solution, in moles per liter (mol/L);

c ₂ —The exact value of the concentration of potassium thiocyanate standard titration solution, the unit is moles per liter (mol/L);

m—The value of the mass of the sample, in grams (g);

M—The value of the molar mass of bromine (Br), in grams per mole (g/mol) (M=79.
9);

20—The dilution factor of the sample
.

The calculation result is expressed to two decimal places
.

Take the arithmetic mean of the two parallel determination results as the determination result
.
The absolute difference between the two parallel determination results is not more than 3% of the arithmetic mean of the two determination values
.

Related links: Test method for mixed catalyst solution of cobalt acetate, manganese acetate and hydrobromic acid (2)