In acidic solution. A 70.0 mL sample of a solution containing Fe2+ requires 70.0 mL of a 0.150 M KMnO4 solution for complete reaction. What is the concentration of the Fe2+ in the original solution?

0.75M Fe²⁺

Explanation:

First, we need to balance the redox reaction in acidic medium. Then, we can obtain moles of KMnO4 and with the reaction moles and molarity of the Fe²⁺ solution:

Redox Balance:

Fe²⁺ → Fe³⁺ + 1e⁻

5e⁻ + 8H⁺ + MnO₄⁻ → Mn²⁺ + 4H₂O

5Fe²⁺ + 5e⁻ + 8H⁺ + MnO₄⁻ → 5Fe³⁺ + 5e⁻ + Mn²⁺ + 4H₂O

Moles of KMnO₄:

70.0mL = 0.0700L * (0.150mol / L) = 0.0105 moles KMnO₄

Moles and molarity Fe²⁺:

0.0105 moles KMnO₄ * (5 moles Fe²⁺ / 1mol KMnO₄) = 0.0525 moles Fe²⁺

In 70.0mL = 0.0700L:

0.0525 moles Fe²⁺ / 0.0700L =

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.