(SEM I) THEORY EXAMINATION 2024-25 ENGINEERING CHEMISTRY

📝 Description of the Question Paper: Engineering Chemistry (BAS102)

This document is a description of the examination paper for the subject Engineering Chemistry, code BAS102, for the B.TECH (SEM I) THEORY EXAMINATION 2024-25.

General Information

Subject: Engineering Chemistry

Subject Code: BAS102

Time: 3 HRS

Maximum Marks: 70 M.MARKS

Instructions: Attempt all Sections. Candidates are advised to choose suitable data for any missing information.

Topics Covered: The paper assesses fundamental concepts and applications across various fields of chemistry relevant to engineering, including: Green Chemistry, Nanomaterials, Stereochemistry, Corrosion, Electrochemistry, Cement Chemistry, Fuels and Combustion, Water Treatment, Polymers, Spectroscopy, and Organic Synthesis.

🏗️ Section-wise Structure

The paper is divided into three sections (A, B, and C), with each question indicating its Cognitive Level (CO Level) for assessment.

SECTION A: Brief Answer Questions

Format: Short answer questions, requiring concise explanations or justifications.

Attempt: All 7 questions are compulsory.

Marking Scheme: $2 \times 7 = 14$ Marks.

Key Content:

Limitations of achieving 100% waste-free chemical manufacturing (Green Chemistry).

Selectivity of light reflection in cholesteric liquid crystals.

Chirality dependence on environment (Theoretical Example).

Conditions for corrosion in the vacuum of space.

Chemical processes causing degradation in dry cell batteries.

Difficulty comparison between chemical and microbial water contamination removal.

Comparison of reshaping ability between thermosetting and thermoplastic polymers.

SECTION B: Explanatory/Detailed Questions

Format: Questions requiring detailed explanations, justifications, and application of principles.

Attempt: Attempt any three out of the five given questions.

Marking Scheme: $7 \times 3 = 21$ Marks.

Key Content:

Comparison of optical transparency between a bulk material and its nanomaterial counterpart.

Biochemical basis for different half-lives of drug enantiomers.

Application of the 12 Principles of Green Chemistry to cement production.

Preference of natural gas over coal for power generation; effect of volatile matter on coal combustion properties.

Discussion of primary degradation mechanisms affecting polymer stability.

SECTION C: Long Answer/Problem-Solving Questions

Format: Each question (3 to 7) has two parts (a and b). Only one part is to be attempted from each question.

Attempt: Attempt any one part from each of the five questions (3, 4, 5, 6, and 7).

Marking Scheme: $7 \times 5 = 35$ Marks.

Key Content:

Question 3: Proposing charge states for a hypothetical $\text{X}_2$ molecule with a bond order of 2.5, OR challenges in replacing conventional paracetamol synthesis with the green route.

Question 4: Determining the structure of an unknown organic compound using a combination of UV, IR, and NMR spectroscopy, OR predicting the structure of a compound with formula $\text{C}_4\text{H}_8\text{O}_2$ based on $\text{}^1\text{H NMR}$ data (singlet at 3.8 ppm, quartet at 1.2 ppm).

Question 5: Explaining the presence of both tri-calcium aluminate and di-calcium silicate in Portland cement despite hydration rate differences, and resolving the hydration heat/water weakening paradox, OR explaining the electrochemical process (dezincification) when brass loses zinc in seawater.

Question 6:

 i. Can hydrogen be classified as both a primary fuel and a secondary fuel? Justify your answer.

ii. A fuel with a GCV of 35 MJ/kg has an NCV of 32 MJ/kg. Explain why there is a difference and how to calculate it

Question 7: Why is it necessary to perform the preparation of Grignard reagents under anhydrous conditions?If 5.0 g of methylmagnesium bromide is reacted with an excess of benzaldehyde.