# A problem in Redox Titrations (Kjeldhal's Method)

• Wrichik Basu
In summary, 31.5% of the NH_4 Cl in the original reaction is converted to NH_3. The equation for the percentage of NH_3 in NH_4 Cl is: \frac {M_{NH_3}} {M_{NH_4Cl}} \times 100\% = 31.5
Wrichik Basu
Gold Member

## Homework Statement

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1.08g of ##NH_4 Cl## is boiled with 62ml ##\frac {N}{2}## ##NaOH## to expel ##NH_3## completely. 44ml of ##\frac {N}{4}## ##HCl## is required to neutralise the excess alkali. Calculate the percentage of ##NH_3 ## in ##NH_4 Cl##.

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## The Attempt at a Solution

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I have found out the number of equivalents of ammonia liberated, which is the same as the number of equivalents of ammonium chloride used, and that of the number of equivalents of ##NaOH## that reacted, keeping in mind to subtract the excess number of equivalents of the alkali.

But, how do I find the weight of ammonia used? In the reaction of ##NH_4 Cl## with ##NaOH##, the oxidation number of Nitrogen doesn't change. So, what is the valency factor or 'n' factor for ammonia to find the equivalent weight? Should I just use Nitrogen's imaginary oxidation number in Ammonia to find the equivalent weight?

Or should I follow a completely different approach?

Hard to say what it is about. A bit nonsensical question (not your fault). Very convoluted way of finding out that

$$\frac {M_{NH_3}} {M_{NH_4Cl}} \times 100\% = 31.5 \%$$

Borek said:
Hard to say what it is about. A bit nonsensical question (not your fault). Very convoluted way of finding out that

$$\frac {M_{NH_3}} {M_{NH_4Cl}} \times 100\% = 31.5 \%$$
What does the M mean?

Molar mass.

Borek said:
Molar mass.
OK, so how should I find Molar Mass from number of equivalents?

Wrichik Basu said:
OK, so how should I find Molar Mass from number of equivalents?

You don't have to, which is why I think this question doesn't make much sense. Most of the information given is completely useless.

Borek said:
You don't have to, which is why I think this question doesn't make much sense. Most of the information given is completely useless.
So, I can conclude that the question is nonsensical, and I mark it solved. Anyways, thank you for your help.

## 1. What is Redox Titrations (Kjeldhal's Method)?

Redox Titrations (Kjeldhal's Method) is a technique used in analytical chemistry to determine the amount of nitrogen in organic compounds. It involves the use of oxidizing agents to convert nitrogen in the sample to ammonia, which is then measured using a titration with a known concentration of acid.

## 2. What is the purpose of Redox Titrations (Kjeldhal's Method)?

The purpose of Redox Titrations (Kjeldhal's Method) is to accurately determine the amount of nitrogen present in a sample. This information is important in various industries, such as food and agriculture, as nitrogen is a crucial nutrient for plant growth and can also indicate the presence of protein in food products.

## 3. What are the steps involved in performing Redox Titrations (Kjeldhal's Method)?

The steps involved in Redox Titrations (Kjeldhal's Method) include digestion, distillation, and titration. In digestion, the sample is heated with a strong acid, such as sulfuric acid, to convert all nitrogen compounds to ammonia. Distillation is then performed to collect the ammonia, which is then titrated with a known concentration of acid to determine the amount of nitrogen present.

## 4. What are the common sources of error in Redox Titrations (Kjeldhal's Method)?

Some common sources of error in Redox Titrations (Kjeldhal's Method) include incomplete digestion of the sample, loss of ammonia during distillation, and inaccurate measurement of titrant or sample volumes. It is important to carefully follow the protocol and use precise techniques to minimize these sources of error.

## 5. How is Redox Titrations (Kjeldhal's Method) used in real-world applications?

Redox Titrations (Kjeldhal's Method) is commonly used in food and agricultural industries to determine the protein content of food products and the availability of nitrogen in fertilizers. It is also used in environmental testing to measure the amount of nitrogen in soil and water samples. This method is also used in pharmaceutical and chemical industries to analyze the purity of substances containing nitrogen.

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