JUST ADDED: JEE Main 2026 (Jan 21) Question Paper with Analysis and Solution Attempt Now →
NEP 2020 Compliant

Competency-Based Assessment Made Simple.

A comprehensive platform for Teachers to create standard question papers and Students to practice Case-Based, Assertion-Reason, and Critical Thinking questions.

866+
Questions
4+
Subjects
100%
NEP Aligned

Generate Papers

Create professional PDF/Word papers with logo, instructions, and mixed question types in minutes.

Start Creating

Question Bank

Explore our repository by Class and Topic. Filter by "Knowledge" or "Competency" levels.

Browse Bank

Self-Regulated Test

For Students. Take timed MCQ tests to check your understanding. Get instant feedback.

Take Test
Pedagogy Shift

Why Competency-Based?

According to NEP 2020, rote learning is out. The focus has shifted to assessing a student's ability to apply concepts in real-life situations.

Case-Based Questions

Questions derived from real-world passages to test analytical skills.

Assertion-Reasoning

Testing the logic behind concepts, not just the definition.

Critical Thinking

Open-ended scenarios that require thinking beyond the textbook.

Marking Scheme
Randomly Fetched Question
Question
Benzene undergoes the following sequence of reactions (see figure). Find the percentage of nitrogen in compound (E).
APPLY COMPETENCY 4 Marks
Concept Application
50%
Calculation / Logic
50%
Target Level
MEDIUM
Unique Feature

More Than Just an Answer Key

We provide complete AI-Powered Explanations for every question.

APPLY COMPETENCY MEDIUM

Q: Benzene undergoes the following sequence of reactions (see figure). Find the percentage of nitrogen in compound (E).

Question Analysis & Solution

Step-by-Step Solution

  1. Reaction 1: Benzene to Nitrobenzene (HNO3/H2SO4) Benzene (C6H6) reacts with concentrated nitric acid in the presence of concentrated sulfuric acid to form nitrobenzene (C6H5NO2).
  2. Reaction 2: Nitrobenzene to Aniline (Fe/HCl) Nitrobenzene (C6H5NO2) is reduced to aniline (C6H5NH2) using iron and hydrochloric acid.
  3. Reaction 3: Aniline to Benzenediazonium Chloride (NaNO2/HCl, 0-5°C) Aniline (C6H5NH2) reacts with sodium nitrite and hydrochloric acid at low temperatures (0-5°C) to form benzenediazonium chloride (C6H5N2Cl).
  4. Reaction 4: Benzenediazonium Chloride to Phenol (H2O/H+, heat) Benzenediazonium chloride (C6H5N2Cl) is hydrolyzed with water in the presence of an acid catalyst and heat to form phenol (C6H5OH).
  5. Reaction 5: Phenol to Picric Acid (Conc. HNO3) Phenol (C6H5OH) reacts with concentrated nitric acid to form 2,4,6-trinitrophenol, also known as picric acid (C6H3N3O7). This is compound E.
  6. Calculate the Molecular Weight of Picric Acid (C6H3N3O7):
    • Carbon (C): 6 * 12.01 = 72.06
    • Hydrogen (H): 3 * 1.01 = 3.03
    • Nitrogen (N): 3 * 14.01 = 42.03
    • Oxygen (O): 7 * 16.00 = 112.00
    Molecular weight = 72.06 + 3.03 + 42.03 + 112.00 = 229.12 g/mol
  7. Calculate the Percentage of Nitrogen in Picric Acid: Percentage of Nitrogen = (Mass of Nitrogen / Molecular Weight of Picric Acid) * 100 Percentage of Nitrogen = (42.03 / 229.12) * 100 = 18.34%

Correct Answer: 18.34

View Full Question Details →