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Class 11 chemistry · linked to Organic chemistry basics · Organic qualitative analysis

Source: CBSE Class 11 chemistry practical syllabus · use your school laboratory manual (NCERT Lab Manual where your school uses it).

Detection of functional groups (Class 11 chemistry practical)

You run the qualitative tests your syllabus lists and match observations to functional groups.

Which sample and which exact reagent strengths you use are school-specific.

Published practice page. Concentrations, masses, and numerical answers come from your school laboratory manual and your own readings — not invented here. Not yet reviewed by a named chemistry reviewer. Version 1.0.0, updated 2026-10-03.

Safety — read before you start

Safety warning. Practise here. Perform the real experiment only in your school lab, with your teacher present.

  • Organic liquids are often flammable.
  • Tollens, chromic, and phenolic reagents need strict teacher control.

Wear: Lab coat, Splash goggles, Gloves, as your teacher directs.

Follow your teacher’s disposal instructions. Do not pour leftovers down a household drain.

Loads only after you tap. Use the lab hands to pick up and use equipment (pointer hidden in the scene). Falls back to a flat diagram if WebGL is unavailable.

Aim

To detect the functional group(s) present in the organic sample(s) assigned in your laboratory manual using the prescribed tests.

Methods and quantities can differ between schools. Follow your teacher's instructions.

Apparatus and chemicals

Apparatus and chemicals
ItemNote
Test tubes and rackClean between tests.
Water bath / burner as directedOnly if the manual’s test needs heat.
DroppersDo not mix droppers between reagents.
Unknown / assigned organic sample (sample)Identity may be withheld until after your report.
Test reagents set (reagents)Litmus, NaHCO₃, neutral FeCl₃, 2,4-DNP, Tollens/Fehling, etc. — only those your manual lists.
Test tubes and reagent bottle for organic tests
Each functional-group test has its own reagent and colour change. Match reagents only to your laboratory manual.

Theory and reaction

Open

Functional groups drive which tests light up. Carboxylic acids liberate CO2 with NaHCO3; phenols often give FeCl3 colours; aldehydes reduce Tollens/Fehling under the conditions taught.

One positive test is a clue, not a full structure proof. Combine tests as your manual sequences them.

Carboxylic acid with sodium bicarbonate gives salt, carbon dioxide, and water.

Procedure

  1. Note physical state, colour, and odour of the sample only as your teacher allows.
  2. Run solubility / litmus checks if the manual starts there.
  3. Perform each functional-group test in the manual’s order. Record exact colour/gas/ppt.Safety: Many organic reagents are flammable or corrosive. No open flames near ether-like solvents.
  4. Conclude which group is present. If ambiguous, say so — do not invent a group.

Observation table

Enter the readings from your school lab in the practical file below. This page does not fill them in for you.

Type the readings in your practical file

Calculation

No titre. Inference table only.

Result

Name the functional group(s) supported by your observations.

Precautions

  • Use small quantities — qualitative does not need a beakerful.
  • Never pipette organics by mouth.

Viva questions

Answer one question at a time. The full answers stay closed until you open them.

Question 1 of 3

A functional group is…

Answer choices

Pick an answer first.

Show all questions and answers

  1. A functional group is…

    Answer: The reactive atom/group that drives chemistry. Reason: It is the characteristic reactive site.

  2. NaHCO₃ test positive with effervescence suggests…

    Answer: Carboxylic acid (typical). Reason: Acids liberate CO₂ with bicarbonate.

  3. Homologues differ by…

    Answer: CH₂. Reason: Successive members differ by a CH₂ unit.

Common mistakes

  • Calling every FeCl₃ colour “phenol” without the manual’s colour key.
  • Skipping the blank / control when the manual asks for one.
  • Heating Tollens reagent too aggressively (explosive silver fulminate risk — follow teacher timing).

Frequently asked questions

Can I do this at home?
No. Use this page to practise the order of ideas and steps. Do the real experiment only in your school laboratory, with your teacher present.

Your practical file

Name, school, and roll number are optional and are not sent anywhere.

The practical file opens on this device.

Review

Not yet reviewed by a named chemistry reviewer. Published for practice only — follow your teacher and laboratory manual for quantities and safety.

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Related notes

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