Engineering Chemistry

Bihar Engineering University, Patna

B.Tech 1st Semester Examination, 2024

Time: 03 HoursCode: 100101Full Marks: 70

Q.1 Choose the correct option/answer the following (Any seven question only):[14]

A sp hybrid orbital contains
1. 25% s-character
2. 75% s-character
3. 50% s-character
4. 100% s-character
Which one is least energetic radiation in Electromagnetic Spectrum.
1. Gamma rays
2. X-Rays
3. IR Rays
4. Radio waves
The \( C=O \) stretching vibration typically appears in the IR spectrum around:
1. 1600 \( cm^{-1} \)
2. 3000 \( cm^{-1} \)
3. 2200 \( cm^{-1} \)
4. 3600 \( cm^{-1} \)
What happens to the \( lambda_{max} \) when conjugation in a molecule increases?
1. It shifts to lower wavelengths (blue shift)
2. It shifts to higher wavelengths (red shift)
3. Both of Them
4. None of Them
The standard hydrogen electrode (SHE) is assigned a potential of:
1. +1.0 V
2. -1.0 V
3. 0.00 V
4. None of them
Scale formation in boilers is due to:
1. Presence of dissolved gases like \( CO_2 \)
2. Presence of dissolved salts like \( CaSO_4 \)
3. Presence of suspended solids
4. Presence of Bacteria
Alkalinity in water is primarily due to the presence of
1. Chlorides and sulfates
2. Calcium and magnesium
3. Hydroxide, carbonate, and bicarbonate ions
4. Nitrates and phosphates
Which one is a example of thermosetting plastic?
1. Polyethylene
2. PVC
3. Bakelite
4. Teflon
Which of the following is a biodegradable polymer?
1. PVA
2. PVC
3. Teflon
4. PHB (Polyhydroxybutyrate)
The product of a Diels-Alder reaction is
1. Linear alkene
2. Six-membered ring
3. Four-membered ring
4. Five-membered ring

Q.2 Solve both questions :[14]

Discuss the nature of metal-carbon bonding (synergistic effect) in metal carbonyls.
What is VSEPR theory? Give its important postulates & predict the structure of \( H_2O \), \( NH_3 \) & \( CH_4 \) using this theory.

Q.3 Solve both questions :[14]

Write note on different types of electronic transition caused by absorption of energy in the UV region.
Explain Chemical shift in NMR spectroscopy. Discuss various factors influencing the chemical shift.

Q.4 Solve both questions :[14]

Discuss in brief about Chemical or Dry corrosion.
What is proximate and ultimate analysis of water. Explain how proximate analysis of a coal sample is done?

Q.5 Solve both questions :[14]

Discuss in brief about the Internal treatment methods for prevention of scale formation in boiler.
What do you mean by Hardness of water. Calculate the temporary & permanent hardness in degree Clark of a water sample having the following analysis: \( Mg(HCO_3)_2 = 146~mg/L \), \( Ca(HCO_3)_2 = 162~mg/L \), \( CaSO_4 = 136~mg/L \), \( MgCl_2 = 95~mg/L \), \( CaCl_2 = 111~mg/L \) & \( NaCl = 50~mg/L \).

Q.6 Solve both questions :[14]

Calculate the amount of lime (92% pure) and soda (98% pure) required for treatment of 30000 litre of water whose analysis is as follows: \( Mg(HCO_3)_2 = 36.5 \) ppm, \( Ca(HCO_3)_2 = 40.5 \) ppm, \( MgSO_4 = 30.0 \) ppm, \( CaCl_2 = 27.75 \) ppm, \( CaSO_4 = 34.0 \) & \( NaCl = 10.0 \) ppm.
Give properties & uses of the polyethylene, polyvinyl Chloride & Buna-S.

Q.7 Solve both questions :[14]

How are polymerization reactions classified on the basis of mechanism. Discuss the mechanism of free radical polymerization reaction.
Differentiate between Thermoplastic & thermosetting resins. Write the synthesis & application of phenol-formaldehyde resin.

Q.8 Solve both questions :[14]

Q.9 Write short notes on any two of the following:[14]