3 Trials 1), 2), 3) Concentration of stadard Na 2 S 2 O 3 solution, M Volume of
ID: 553061 • Letter: 3
Question
3 Trials 1), 2), 3)
Concentration of stadard Na2S2O3 solution, M
Volume of Na2S2O3 used, mL = 1)22.7, 2)23.6, 3)23.5
Amount of Na2S2O3 used, mol = 1)?, 2)?, 3)?
Amount of Cu2+ in unknown sample, mL = 1)? 2)? 3)?
Volume of original Cu2+ solution used, mL = 1)10, 2)10, 3)10
Concentration of Cu2+ in original solution, M = 1)? 2)? 3)?
Average concentration of Cu2+ = ?
Solver for ?
Volumetric Analysis of Cu2 Objective The concentration of copper (II) ion in a solution will be determined by titration Introduction The quantitative determination of the amount of metallic ions in a sample can be accomplished by precipitating the solution according to the equation, 2 Ci?-(aq) + 4 raq) 2 Cul (s) + 11 (aq). white brown solid The iodine, 12, imparts a brown colour to the solution. The solution will then be titrated with sodium thiosulphate, Na S,Os, which reacts with the /, produced in reaction (1) according to the equation 25,0, (aq) +12 (aq) S,Or (aq) + 2 raq) colourless brown The white, solid copper () iodide will remain in the reaction flask throughout the titration. As the titration prog resses, the brown colour progressively changes colour to light brown and then to yellow as the quantity of iodine is depleted. The end point of the titration is reached when the pale yellow colour, signalling the last traces of iodine, just disappears. This colour change from yellow to white is rather difficult to observe, therefore starch is added to the solution when it becomes yellowish in order to facilitate detection of the end point of the titration. Starch forms a deep blue coloured complex with iodine 12 (aq) + starch 12-Starch brown colourless blue Thus the end point occurs when the mixture in the flask just turns becomes white 2 s,0, (aq) + 12-starch Sor (aq) + 2(aq) + starch colourless blue colourless colourless The balanced overall stoichiometric equation for the volumetric analysis of Cu? can be obtained by adding equations (1) and (2). From the number of moles of s,o used and the mole relationship between ,o and Cu, the number of moles of Cu and its concentration in the original Cu? can be determined.Explanation / Answer
the molarity of the standard thiosulphate solution is M, (Data is missing Let M) so as molarity to find the absolute number of moles. so if we take 22.7 mL M mol/lit which gives the number of the mole in solution = (22.7* M) / 1000 = 0.0227M Mole of Na2S2O3.
for the estimation of copper solution
the strength of hypo solution S1= M
the volume of hypo solutionV1 =22.7 mL
volume of copper solution V2 =10 mL
let the strength of the copper solutionS2 = ?
as we know V1S1=V2S2
M*22.7 = 10* S2
S2 = 2.27*M
strength of copper solution 2.27* M
as we know
1000 mL of 1 (N) Na2S2O3 solution = 63.5 g of copper
1 mL of 1 (N) Na2S2O3 solution = 0.063 g of copper
now 22.7 mL of M (N) Na2S2O3 solution = (0.063*22.7*M) g of copper
= 1.43* M g of copper
now 10 mL solution contains 1.43 *M g of copper
1000 mL solution contains [(1.43 *M * 1000) / 10] g of copper
= 143*M g of copper
amount of copper in the given solution is( 143 * M) g /L
similarly for the other two titration
for 23.6 mL of thiosulphate solution
V1S1=V2S2
S2 = 2.36 * M
similarly for 23.6 mL of M Na2S2O3 solution = ( 0.063* M * 23.6) g copper
so 10 ml unknown copper solution contains = (0.063*M*23.6)
1000 mL contins = (0.063*M*23.6*1000)/10
= 148.68 * M g of copper
for the case of 23.5
S2 = 2.3* M
similarly for 23.5 mL of M Na2S2O3 solution = ( 0.063* M * 23.5) g copper
so 10 ml unknown copper solution contains = (0.063*M*23.5)
1000 mL contins = (0.063*M*23.5*1000)/10
= (148.05 * M )g copper
so the avarage concentration of the original Cu+2 solution = {(148.05 + 148.63 + 143) *M }/ 3
= 146.56 *M
Please put the value of M and you will get the data of all steps
thank you
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