Question 1

Define hard water and soft water.

Accepted Answer

Hard water does not easily form lather with soap due to dissolved calcium and magnesium salts, while soft water readily forms lather.

Question 2

What is the unit of hardness in Clarke's system?

Accepted Answer

The unit of hardness in Clarke's system is Degree Clarke (°Cl). It represents parts of equivalent calcium carbonate per 70,000 parts of water.

Question 3

Define Calorific value of a fuel.

Accepted Answer

Calorific value is the total amount of heat liberated when a unit mass or unit volume of a fuel is burnt completely.

Question 4

What is the composition of Water Gas?

Accepted Answer

Water gas is primarily a combustible mixture of Carbon monoxide (CO) and Hydrogen (H₂) in roughly equal proportions.

Question 5

Define corrosion.

Accepted Answer

Corrosion is the gradual destruction or degradation of a metal or alloy by chemical or electrochemical reaction with its environment.

Question 6

What are the raw materials used for the manufacture of Portland cement?

Accepted Answer

The raw materials for Portland cement are Calcareous materials (providing lime) and Argillaceous materials (providing silica, alumina, and iron oxide).

Question 7

Define glass.

Accepted Answer

Glass is an amorphous, transparent or translucent supercooled liquid of infinite viscosity, lacking a true crystalline structure.

Question 8

What is the significance of Saponification value of a lubricant?

Accepted Answer

The saponification value helps to determine the proportion of animal or vegetable fatty oils present in a compounded lubricating oil.

Question 9

What is sacrificial anode?

Accepted Answer

A sacrificial anode is a highly active metal connected to a base metal structure to protect the base metal from corrosion.

Question 10

Define an electrophile with example.

Accepted Answer

An electrophile is an electron-deficient chemical species that seeks an electron pair to form a covalent bond during a reaction.

Question 11

Explain Zeolite process for water softening with diagram.

Accepted Answer

The Zeolite process removes hardness by passing water through a bed of active sodium zeolite, which undergoes an ion-exchange reaction to replace calcium and magnesium ions with non-hardness causing sodium ions.

Question 12

Explain Ultimate analysis of coal and its significance.

Accepted Answer

Ultimate analysis is the precise quantitative determination of the fundamental chemical elements in coal: Carbon, Hydrogen, Nitrogen, Sulphur, and Oxygen. It is crucial for calculating absolute theoretical heating values and precise combustion oxygen requirements.

Question 13

Explain the mechanism of electrochemical (wet) corrosion.

Accepted Answer

Electrochemical (wet) corrosion requires a conducting liquid and occurs when anodic and cathodic areas form on a metal surface, driving a destructive galvanic cell. The metal dissolves at the anode, while reduction occurs at the cathode.

Question 14

Discuss the classification of lubricants with examples.

Accepted Answer

Lubricants are critically essential for reducing friction and are classified by physical state into liquid (oils), semi-solid (greases), and solid (graphite/MoS2) lubricants, each tailored for specific operational environments.

Question 15

Describe the synthesis and uses of Aspirin.

Accepted Answer

Aspirin is synthesized industrially via the acetylation of salicylic acid using acetic anhydride, catalyzed by an acid. It functions widely as a potent analgesic, antipyretic, and anti-inflammatory drug.

Question 16

Explain the setting and hardening of cement with chemical equations.

Accepted Answer

The setting and hardening of cement are complex, exothermic processes driven by the rapid hydration of Tricalcium Aluminate for initial set, and the slow, sustained hydration of calcium silicates for ultimate mechanical strength.

Question 17

Explain the Bergius process for manufacture of synthetic petrol.

Accepted Answer

The Bergius process is an industrial technique to synthesize high-quality liquid petrol from solid coal. It involves the direct, high-pressure catalytic hydrogenation of a coal-oil paste at extremely high temperatures.

Question 18

Explain the EDTA method for determination of total hardness of water. Numeric…

Accepted Answer

The EDTA complexometric method is the standard for determining total water hardness by titrating with EDTA at pH 10 using EBT indicator. The numerical calculation yields a total hardness of 200 ppm, temporary hardness of 100 ppm, and permanent hardness of 100 ppm.

Question 19

Explain the construction and working of Boy's gas calorimeter with diagram. N…

Accepted Answer

Boy's gas calorimeter measures the calorific value of gaseous fuels by burning a known volume and measuring the heat absorbed by circulating cooling water. The numerical yields a Gross Calorific Value (GCV) of 2318 kcal/m³ and a Net Calorific Value (NCV) of 2082.2 kcal/m³.

Question 20

What is differential aeration corrosion? Explain with examples like waterline…

Accepted Answer

Differential aeration corrosion occurs when different areas of a metal surface are exposed to varying concentrations of oxygen. The area with less oxygen becomes anodic and corrodes rapidly, while the highly oxygenated area becomes cathodic and is protected.

Question 21

Explain the manufacture of glass by pot furnace method. Discuss the various t…

Accepted Answer

The pot furnace method involves melting specialized glass batches in large refractory fireclay pots. Different chemical compositions, like soda-lime, borosilicate, and flint glass, yield glasses with unique thermal, optical, and chemical properties.

Question 22

Explain the mechanism of $S_N2$ reaction with suitable example. Also discuss …

Accepted Answer

The SN2 mechanism is a concerted, one-step nucleophilic attack characterized by complete stereochemical inversion. The Anti-Markovnikov addition of HBr to asymmetric alkenes in the presence of peroxide proceeds via a free-radical chain mechanism, attaching bromine to the less substituted carbon.

Engineering Chemistry