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5. A solution of sodium thiosulfate, Na2S2O3, is standardized using pure potassium dichromate, K2Cr2O7. The standardization first involved reaction of 0.2263 grams of K2Cr2O7 with excess KI and excess acid to produce I2 according to the chemical equation: Cr2O7^2- (aq) + 6 I^- (aq) + 14 H^+ (aq) ? 2 Cr^3+ (aq) + 3 I2 (aq) + 7 H2O (l) The I2 produced was then titrated with the Na2S2O3 solution; requiring 44.32 mL of the Na2S2O3 solution to reach the end point. The reaction that occurred between I2 and S2O3^2- is given by the equation: I2 (aq) + 2 S2O3^2- (aq) ? 2 I^- (aq) + S4O6^2- (aq) Calculate the molarity of the Na2S2O3 solution.

          5. A solution of sodium thiosulfate, Na2S2O3, is standardized using pure potassium dichromate, K2Cr2O7. The standardization first involved reaction of 0.2263 grams of K2Cr2O7 with excess KI and excess acid to produce I2 according to the chemical equation:

Cr2O7^2- (aq) + 6 I^- (aq) + 14 H^+ (aq) ? 2 Cr^3+ (aq) + 3 I2 (aq) + 7 H2O (l)

The I2 produced was then titrated with the Na2S2O3 solution; requiring 44.32 mL of the Na2S2O3 solution to reach the end point. The reaction that occurred between I2 and S2O3^2- is given by the equation:

I2 (aq) + 2 S2O3^2- (aq) ? 2 I^- (aq) + S4O6^2- (aq)

Calculate the molarity of the Na2S2O3 solution.

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5. A solution of sodium thiosulfate, Na2S2O3, is standardized using pure potassium dichromate, K2Cr2O7. The standardization first involved reaction of 0.2263 grams of K2Cr2O7 with excess KI and excess acid to produce I2 according to the chemical equation:

Cr2O7^2- (aq) + 6 I^- (aq) + 14 H^+ (aq) ? 2 Cr^3+ (aq) + 3 I2 (aq) + 7 H2O (l)

The I2 produced was then titrated with the Na2S2O3 solution; requiring 44.32 mL of the Na2S2O3 solution to reach the end point. The reaction that occurred between I2 and S2O3^2- is given by the equation:

I2 (aq) + 2 S2O3^2- (aq) ? 2 I^- (aq) + S4O6^2- (aq)

Calculate the molarity of the Na2S2O3 solution.

Added by Stephanie G.

Chemistry: Structure and Properties

Nivaldo Tro 2nd Edition

Instant Answer

Solved by Expert Supreeta N

05/16/2023

Step 1

We can do this by using its molar mass, which is approximately 294.2 g/mol. Moles of K2Cr2O7 = (0.2263 g) / (294.2 g/mol) = 0.000769 mol Now, we can find the moles of I2 produced using the stoichiometry of the reaction: Moles of I2 = (0.000769 mol K2Cr2O7) * (3 Show more…

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A solution of sodium thiosulfate, Na2S2O3, is standardized using pure potassium dichromate, K2Cr2O7. The standardization first involved the reaction of 0.2263 grams of K2Cr2O7 with excess KI and excess acid to produce I2 according to the chemical equation: Cr2O7^2- (aq) + 6 I^- (aq) + 14 H+ (aq) -> 2 Cr^3+ (aq) + 3 I2 (aq) + 7 H2O (l) The I2 produced was then titrated with the Na2S2O3 solution, requiring 44.32 mL of the Na2S2O3 solution to reach the end point. The reaction that occurred between I2 and S2O3^2- is given by the equation: I2 (aq) + 2 S2O3^2- (aq) -> 2 I^- (aq) + S4O6^2- (aq) Calculate the molarity of the Na2S2O3 solution.

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00:01 Hi, in this question we are given that a solution of na2so4 that is na2s2o3 is standardized using pure k2cr2o7.

00:12 The standardization involves the reaction of k2cr2o7 with excess of ki and excess of acid to produce i2.

00:25 Here is the net chemical equation and we are given with the mass of k2cr2o7 as 0 .226 kg.

00:32 Here the produced i2 is titrated with na2so4 that is na2s2o3 and in this the volume used of na2s2o3 is 44 .32 ml that is equal to 0 .04432 liters in order to reach the end point.

00:55 Here we are asked to calculate the molarity of na2s2o3.

01:02 First of all we will calculate moles of k2cr2o7 as it is equal to mass over its molar mass.

01:14 We can substitute the values here in this manner.

01:17 Now we can eliminate the common gram unit from here and on solving we are getting moles of k2cr2o7 or the moles of cr2o7 2 - is equal to 0 .000769 mole.

01:33 Now we can calculate the moles of i2 by using the stoichiometric coefficients.

01:41 For this here we need to write cr2o7 2 - and here we need to write the i2.

01:48 According to stoichiometry of reaction we can see 1 mole of cr2o7 2 - produces 3 moles of i2.

01:56 For example, we are having 0 .000769 moles of cr2o7 2 - it will produce 3 mole divided by 1 mole into 0 .000769 moles.

02:13 From here we can eliminate the common mole unit and on solving we are getting moles of i2 is equal to 0 .002307 mole.

02:24 Now we are having moles of i2...

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