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excess KI
Sulphuric acid helps in maintaining pH around 3-4 which further helps in liberation of iodine upon adding KI solution.
teri maa ki chut sale tum btao.....
55 ml of a 4.05 M solution of KI solution contains 55*4.05=222.75 millimoles. 20.5 ml of the diluted solution contains 3.8g of KI,so no.of moles of KI=3.8/(mol.wt of KI=165.9) is 22.9 millimoles. molarity of final diluted solution=22.9/20.5=1.117M since the no. of moles of KI present in initial and final solution are same. let.V(in ml) be the final volume of diluted solution. 222.75/V=1.117 V=199.41 ml final volume =199.41 ml
ki is added to liberate iodine gas . this liberated iodine gas was then titrated with sodium thiosulphate to give a permanent white precipitate. this white precipitate indicates the endpoint of the titration..
excess KI
Sulphuric acid helps in maintaining pH around 3-4 which further helps in liberation of iodine upon adding KI solution.
teri maa ki chut sale tum btao.....
55 ml of a 4.05 M solution of KI solution contains 55*4.05=222.75 millimoles. 20.5 ml of the diluted solution contains 3.8g of KI,so no.of moles of KI=3.8/(mol.wt of KI=165.9) is 22.9 millimoles. molarity of final diluted solution=22.9/20.5=1.117M since the no. of moles of KI present in initial and final solution are same. let.V(in ml) be the final volume of diluted solution. 222.75/V=1.117 V=199.41 ml final volume =199.41 ml
0.18M
Molarity = moles of solute/Liters of solution. get moles KI 2.822 grams KI (1 mole KI/166 grams) = 0.017 moles KI ( 67.94 ml = 0.06794 Liters ) Molarity = 0.017 moles KI/0.06794 Liters = 0.2502 M KI
ki is added to liberate iodine gas . this liberated iodine gas was then titrated with sodium thiosulphate to give a permanent white precipitate. this white precipitate indicates the endpoint of the titration..
Find moles potassium iodide first.2.41 grams KI (1 mole KI/166 grams) = 0.01452 moles KIMolarity = moles of solute/Liters of solution ( 100 ml = 0.1 Liters )Molarity = 0.01452 moles KI/0.1 Liters= 0.145 M KI solution================
dissolve iodine crystals in a saturated KI(potassium iodide) solution
On addition of the KI to your copper (II) solution, you formed Copper (I) iodine solid and produced the tri-iodide ion. It is the tri-iodide ion that you are titrating with the sodium thiosulfate. The tri-iodine ion is what itercalates into the starch molecules to form the dark blue color you are using as an end point in the titration. Some the the tri-iodide ion formed will adsorb to the surface of the solid copper (I) iodine formed. This must be desorbed for a complete titration. The addition of the potassium thiocyanate, displaces the adsorbed tri-iodine ion, and liberates it for titration.
Use 'I2 + KI ' solution: 0.1% 'Iodine-Iodide' turns purple blue with starch, very sensitive test!
V*c*M = 276(mL)*0.001(L/mL)*0.50(mol KI/L)*166.0(g KI/mol KI) = 22.9 g KI