Question

Хлор,полученный при электролизе 250 г раствора NaCl,пропустили через избыток раствора KI и получили 6,35 г йода.Найдите массовую долю NaCl в исходном растворе.

Answer 1

Решение в прикрепленном фото.

Answer 2

Calculation of the Mass Fraction of NaCl in the Original Solution

To find the mass fraction of NaCl in the original solution, we need to calculate the amount of NaCl present in the solution and divide it by the total mass of the solution.

Given information: - Mass of the solution = 250 g - Mass of iodine (I2) produced = 6.35 g

To calculate the mass of NaCl in the solution, we can use the stoichiometry of the reaction between NaCl and KI:

2NaCl + 2KI -> 2NaI + Cl2

From the balanced equation, we can see that 2 moles of NaCl react with 2 moles of KI to produce 2 moles of NaI. This means that the molar ratio between NaCl and NaI is 1:1.

Since the molar mass of NaI is 149.89 g/mol, we can calculate the moles of NaI produced:

moles of NaI = mass of iodine (I2) / molar mass of NaI moles of NaI = 6.35 g / 149.89 g/mol

Next, we can calculate the moles of NaCl present in the solution:

moles of NaCl = moles of NaI

Finally, we can calculate the mass fraction of NaCl in the original solution:

mass fraction of NaCl = (moles of NaCl * molar mass of NaCl) / mass of the solution

Let's perform the calculations:

moles of NaI = 6.35 g / 149.89 g/mol = 0.04237 mol moles of NaCl = 0.04237 mol

Now, we need to find the molar mass of NaCl. The molar mass of Na is 22.99 g/mol, and the molar mass of Cl is 35.45 g/mol. Therefore, the molar mass of NaCl is:

molar mass of NaCl = 22.99 g/mol + 35.45 g/mol = 58.44 g/mol

Finally, we can calculate the mass fraction of NaCl:

mass fraction of NaCl = (0.04237 mol * 58.44 g/mol) / 250 g

The mass fraction of NaCl in the original solution is approximately 0.0098 or 0.98%.

Please note that the calculations provided above are based on the given information and assumptions. If there are any additional details or factors that need to be considered, please let me know.