(SEM I) ENGINEERING CHEMISTRY THEORY EXAMINATION 2024-25

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📄 Question Paper Description (QP25DP2_290)

This document is a Theory Examination Question Paper for the B.Tech (Semester I) course in Engineering Chemistry, subject code BAS102, for the 2024-25 academic session.

Subject: Engineering Chemistry

Subject Code: BAS102

Level: B.Tech (SEM I) Theory Examination

Time: 3 HRS

Max Marks: 70

The instruction to candidates is to Attempt all Sections and choose missing data suitably.

🧪 Structure and Content Analysis

The paper is divided into three compulsory sections: Section A, Section B, and Section C.

Section A: Brief Answer Questions (14 Marks)

This section contains seven compulsory questions (Q. No. 1, parts a-g), each worth 2 marks, requiring concise answers on fundamental concepts.

Key Topics:

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

Reflection properties of cholesteric liquid crystals.

Conditions for a molecule to be chiral in one environment and achiral in another.

Possibility and conditions for corrosion in a space vacuum.

Chemical processes leading to the degradation of a dry cell battery.

Difficulty in removing chemical vs. microbial water contamination.

The difference in reshaping properties between thermosetting and thermoplastic polymers.

Section B: Medium Answer Questions (21 Marks)

Candidates must attempt any three out of the five questions (Q. No. 2, parts a-e), with each question carrying 7 marks. These questions involve justification, explanation, and critical discussion.

Key Topics:

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

The biochemical basis for the different half-lives of drug enantiomers.

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

Preference for natural gas over coal for power generation and the effect of volatile matter on coal combustion.

Discussion of primary degradation mechanisms affecting polymer stability in different environments.

Section C: Long Answer/Numerical Questions (35 Marks)

This section is composed of five main questions (Q. No. 3 to Q. No. 7). Candidates must attempt any one part (a or b) from each of the five questions, with each part carrying 7 marks.

Q. No.	Topic Area	Part (a)	Part (b)
3	Molecular/Green Chemistry	Propose charge states/electronic configuration for a hypothetical molecule $\text{X}_2$ with a bond order of 2.5.	Challenges in replacing the conventional paracetamol synthesis with the green route.
4	Spectroscopy	Use of a combination of UV, IR, and NMR spectroscopy to determine the structure of an unknown organic compound (with example).	Predict the structure of a compound ($\text{C}_4\text{H}_8\text{O}_2$) based on $^1\text{H NMR}$ data (singlet at 3.8 ppm, quartet at 1.2 ppm).
5	Materials/Corrosion	Portland cement paradox: Presence of $\text{C}_3\text{A}$ and $\text{C}_2\text{S}$, and why excess water weakens concrete despite the heat of hydration.	Explain the electrochemical process (dezincification) when brass loses zinc in seawater.
6	Water/Fuel	Reasons why the Zeolite process is unsuitable for water with high $\text{Fe}$ and $\text{Mn}$ concentrations, and a numerical calculation for total hardness in $\text{ppm}$ as $\text{CaCO}_3$.	Justification of hydrogen as a primary and secondary fuel, and explanation/calculation of the difference between GCV and NCV.
7	Organic/Polymer	Necessity of anhydrous conditions for Grignard reagent preparation, and a numerical calculation for the expected yield of benzyl alcohol (85% yield).	Explanation of why water and oils do not adhere to Teflon, and a numerical calculation of the volume of a piece of Teflon (given mass and density).