Academic session 2026-27, Chapter 9 in the current curriculum.
Welcome to the NCERT Solutions for Class 11 Biology - Chapter Biomolecules. This page offers a step-by-step solution to the specific question from Exercise 1, Question 13: Find out a qualitative test for proteins, fats and oils, amino acids and test any fruit juice, saliva, sweat and urine for them.. With detailed answers and explanations for each chapter, students can strengthen their understanding and prepare confidently for exams. Ideal for CBSE and other board students, this resource will simplify your study experience.
(a) Test for protein
Biuret’s test – If Biuret’s reagent is added to protein, then the colour of the reagent changes from light blue to purple.
(b) Test for fats and oils
Grease or solubility test
(c) Test for amino acid
Ninhydrin test – If Ninhydrin reagent is added to the solution, then the colourless solution changes to pink, blue, or purple, depending on the amino acid.
|
Item |
Name of the test |
Procedure |
Result |
Inference |
|
|
1. |
Fruit juice |
Biuret’s test |
Fruit juice + Biuret’s reagent |
Colour changes from light blue to purple |
Protein is present. |
|
|
|
Grease test |
To a brown paper, add a few drops of fruit juice. |
No translucent spot |
Fats and oils are absent or are in negligible amounts. |
|
|
|
Ninhydrin test |
Fruit juice + Ninhydrin reagent + boil for 5 minutes |
Colourless solution changes to pink, blue, or purple colour |
Amino acids are present. |
|
2. |
Saliva |
Biuret’s test |
Saliva + Biuret’s reagent |
Colour changes from light blue to purple |
Proteins are present. |
|
|
|
Grease test |
On a brown paper, add a drop of saliva. |
No translucent spot |
Fats/oils are absent. |
|
|
|
Ninhydrin test |
Saliva + Ninhydrin reagent + boil for 5 minutes |
Colourless solution changes to pink, blue, or purple colour |
Amino acids are present. |
|
3. |
Sweat |
Biuret’s test |
Sweat + Biuret’s reagent |
No colour change |
Proteins are absent. |
|
|
|
Solubility test |
Sweat + Water |
Oily appearance |
Fats/oil may be present. |
|
|
|
Ninhydrin test |
Sweat + Ninhydrin reagent + boil for 5 minutes |
No colour change, solution remains colourless |
Amino acids are absent. |
|
4. |
Urine |
Biuret’s test |
Few drops of urine + Biuret’s reagent |
Colour changes from light blue to purple |
Proteins are present. |
|
|
|
Solubility test |
Few drops of urine + Water |
Little bit of oily appearance |
Fats may or may not be present. |
|
|
|
Ninhydrin test |
Few drops of urine + Ninhydrin reagent + boil for 5 minutes |
Colourless solution changes to pink, blue, or purple colour depending on the type of amino acid |
Amino acids are present. |
NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:
Stay updated with our latest educational content and study tips
It’s not about starting over if you took a break to care for children, take care of yourself, be healthy or for any other reason. This is a realistic strategy for the recovery of skills, selection of the right job, and overcoming the resume problem. One year, three years or 10 years of a career … Read more
Read MoreThere’s no need to score 95% or achieve a JEE/NEET rank. You don’t need to score 95% or rank in JEE/NEET to build a solid career. A candid and pragmatic guide to the routes that actually work for students who have an average mark and what to do when faced with the options. If … Read more
Read MoreAI tools, online platforms that are much cheaper than coaching centres and the changing idea of what “structure” even means have upended this argument more in the past two years than in the decade preceding it. Here’s what is really the case for 2026 – and what has actually stayed the same. If you look … Read more
Read MoreStarting to make a new career after 30 isn’t a start from scratch. Marketing, teaching, financial, retail, healthcare, sales and other professionals can pursue careers in technology by applying the existing knowledge and skills they have acquired to new technology skills. There are various ways to enter the technology industry, such as in IT support, … Read more
Read MoreCalculate percentage from obtained marks and total marks.
Welcome to the NCERT Solutions for Class 11 Biology - Chapter . This page offers a step-by-step solution to the specific question from Excercise 1 , Question 13: Find out a qualitative test for proteins, fats and oils, amino acids and test any fruit juice, saliv....
Fresh educational articles and updates.
Most-read articles from SaralStudy.
Fast access to frequently used study resources.
Recently viewed articles based on SaralStudy activity.
Add Comment