Question

Consider the following unbalanced net ionic equation: NO2- + MnO4= NO3- + Mn2+ (in acidic solution). What is the molarity of a sodium nitrite, NaNO2, solution if 30.0 mL of it just reacts with 0.238 grams of KMnO4.

Answer 1

The molarity of the NaNO2 solution is found by calculating the moles of KMnO4 from its given mass, using the balanced reaction's stoichiometry to find the moles of NaNO2, and then dividing by the volume of the NaNO2 solution.

Step-by-step explanation:

The student is tasked with finding the molarity of a sodium nitrite (NaNO2) solution. To do this, we balance the provided net ionic equation in an acidic solution: NO2- + MnO4- → NO3- + Mn2+, and determine the stoichiometry between NaNO2 and KMnO4. Since the mass of KMnO4 is given, we first calculate its moles, then use the stoichiometry to find moles of NaNO2 that reacted. The volume of the NaNO2 solution is used to find its molarity.

To calculate the molarity of the NaNO2 solution:

1. First, determine the molar mass of KMnO4 using the periodic table.
2. Then calculate the number of moles of KMnO4 using the mass provided and its molar mass.
3. Using the balanced equation, find the stoichiometric ratio and calculate the moles of NaNO2 that reacted with KMnO4.
4. Finally, use the moles of NaNO2 and the volume of the solution (30.0 mL converted to liters) to find the molarity of the NaNO2 solution.

Answer 2

To calculate the molarity of a NaNO2 solution that reacts with KMnO4, the student must balance the redox equation, determine the molar mass of KMnO4, calculate the moles of reactants, and use the volume of the NaNO2 solution.

Step-by-step explanation:

The student has asked about the molarity of a sodium nitrite, NaNO2, solution given the reaction with KMnO4. To find the molarity, we must first balance the given net ionic equation in acidic solution. Assuming stoichiometric balance, we:

1. Determine the molar mass of KMnO4.
2. Calculate the number of moles of KMnO4 using its mass and molar mass.
3. Use stoichiometry to find the moles of NaNO2 that reacted with the given moles of KMnO4.
4. Calculate the molarity of NaNO2 using its moles and the volume of the solution (30.0 mL).

In a balanced redox reaction in acidic solution, the number of electrons lost by the reducing agent (NO2-) is equal to the number of electrons gained by the oxidizing agent (MnO4-), leading to the formation of NO3- and Mn2+ ions.