The amount of i3-(aq) in a solution can be determined by titration with a solution containing a known concentration of s2o3^2-(aq) (thiosulfate ion).

the determination is based on the net ionic equation

2s2o3^2-(aq)+i3^-(aq) > s4o6^2-(aq)+31^-(aq)

given that it requires 35.8 ml of 0.350 m na2s2o3(aq) to titrate a 30.0-ml sample of i3^-(aq) calculate the molarity of i3^-(aq) in the solution

molarity of I3^-(aq) in the solution = 0.21 M

Explanation:

We are given the balanced chemical reaction and the volume and molarity of the  Na₂S₂O₃ so we can calculate the moles of the thiosulfate that were required, and then can calculate the molarity the  I₃⁻ by the definition of molarity.

First lets  convert the volume of Na₂S₂O₃ to liters:

35.8 mL x 1 L/1000 mL = 0.0358 L

# moles Na₂S₂O₃ = 0.350 mol/L x 0.0358 L = 0.0125 mol

From the stoichiometry of the reaction we know 2 mol Na₂S₂O₃ s react with 1 mol I₃⁻ , therefore mol of I₃⁻  will be given by

1 mol I₃⁻ / 2 mol Na₂S₂O₃  x 0.0125 mol Na₂S₂O₃ = 0.0063 mol  I₃⁻

and its molarity is:

0.0063 mol  I₃⁻ / 0.030 L = 0.21 M

d. temperate deciduous forest

answer: - 3.) the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

solution: - as per the rules, oxidation number of oxygen in its compounds is -2. the sum of oxidation numbers of all the elements of a molecule or compound is zero.

also, the oxidation number in elemental form is zero.

in no, the oxidation number of o is -2 so the oxidation number of n is +2 so that the sum is zero.

similarly, the oxidation number of c in co is +2 and o is -2.

on product side the oxidation number of n is 0 as it is in the elemental form() .

oxidation number of c in carbon dioxide is +4 as there are two oxygen in it and we know that each oxygen is -2.

so, oxidation number of n is changing from +2 to 0 and the oxidation number of c is changing from +2 to +4.

since nitrogen is reduced and hence no is acting as an oxidizing agent. carbon is oxidized and so co is acting as a reducing agent.

so, the right choice is number 3.)the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.