Kjeldahl Method of Nitrogen Estimation Procedure and MCQ for Competitive Exams

Kjeldahl Method of Nitrogen Estimation :-

Kjeldahl Method is Used to determination of amount of Nitrogen in given sample.

It is official method. It is also used to determine nitrogen content in food , soft drinks, and calculation of protein.

Procedure :-

There are mainly three steps :-

1. Digestion :-  sample is first digested in strong sulfuric acid in the presence of a catalyst, which helps in the conversation of the amine Nitrogen to ammonium ions.

2. Distillation :- The ammonium ions are then converted into ammonia gas, heated and distilled. The ammonia gas is led into a trapping solution where it dissolve and become an ammonium ions once again.

3. Titration :- Finally the amount of the ammonia that has been trapped is determined by titration with a standard solution.

The result can be expressed in %N,%NH3, or protein (%N *factor).

MCQ .

1. Which method are used to determination  of Nitrogen in sample?

A. Karl fischer titration

B. OFC

C. Kjeldahl Method

D. None of this.

2. Kjeldahl Method which acid are used in digestion step ?

A. Sulfuric acid

B. Hydrochloric acid

C. Nitric acid

D. None of this

3. Which method is used to determination of protein contain in food ?

A. Karl fischer titration

B. OFC

C. Kjeldahl Method

D. None of this.

4. Which step ammonium ions converted into a ammonia gas ?

A. Digestion

B. Distillation

C. Titration

D. Back titration.

5. Which sentence is false about Kjeldahl Method ?

A. It is used to determination of Nitrogen.

B. It is official method.

C. Sulfuric acid are used in digestion step.

D. It is also used to determination of moisture content.

Answer key

1. C

2. A

3. C

4. B

5. D