Engineering Chemistry (BAS102) - AKTU Question Paper 2024-25

No, completely waste-free chemical manufacturing is practically difficult. Some waste is always produced due to side reactions, incomplete conversion, impurities, separation processes, energy use, and limitations of available technology. Green chemistry aims to minimize waste as much as possible.

Cholesteric liquid crystals have a helical molecular arrangement. They selectively reflect light whose wavelength matches the pitch of the helix. Therefore, only certain wavelengths are reflected, while the remaining wavelengths pass through the material.

Yes. A molecule may become chiral when its molecular motion or conformation is restricted by a particular environment.

Example: A rapidly rotating substituted biphenyl may behave as achiral in solution, but when rotation is restricted in a rigid medium, stable chiral conformations can form.

Yes, corrosion can occur in space under certain conditions. Although ordinary electrochemical corrosion is very low in vacuum, materials can still degrade due to atomic oxygen, solar radiation, high-energy particles, and traces of moisture or reactive gases.

A dry cell loses charge due to self-discharge. Slow internal redox reactions continue even when the battery is not connected to a circuit.

These unwanted reactions gradually consume the active materials of the electrodes and electrolyte, causing loss of stored chemical energy.

Chemical contamination is generally more difficult to remove because many dissolved chemicals, such as heavy metals, salts, pesticides, and toxic organic compounds, cannot be removed by simple filtration or disinfection.

They often require special methods such as adsorption, ion exchange, reverse osmosis, or chemical treatment.

Thermosetting polymers have a highly cross-linked three-dimensional network. On heating, they do not soften; instead, they decompose because the strong cross-links prevent molecular movement.

Thermoplastic polymers have linear or slightly branched chains with weaker intermolecular forces. Therefore, they soften on heating and can be reshaped.