Molecules

What is the principal of the EDTA method for water hardness estimation?

It is a complexometric method for determining the total hardness of water.

How is total hardness calculated from a sample containing Ca(HCO3)2, Mg(HCO3)2, CaSO4, and MgSO4?

By summing the hardness contributed by each compound in appropriate units.

Define Hardness of Water.

Hardness of water refers to the amount of dissolved calcium and magnesium ions present.

What are the different units of hardness for water?

Common units include ppm, mg/L, and degrees Clarke or French.

Discuss the principle of the EDTA method for hardness determination.

EDTA forms stable complexes with metal ions that are directly related to the hardness.

What was the alkalinity type of a water sample that required 20 ml of N/50 H2SO4 for neutralization?

It indicates the presence of bicarbonates and carbonates converted to CaCO3 equivalents.

Why do we express hardness of water in terms of CaCO3 equivalents?

It standardizes different hardness contributions to a common reference.

What method is used to determine alkalinity in water samples?

Acid titration method using a standardized acid.

Differentiate between hard water and soft water.

Hard water contains high levels of calcium and magnesium, while soft water has low levels.

Explain the term 'Caustic embrittlement'.

It refers to the failure of steel due to corrosion caused by caustic soda in boilers.

How is water softened using the zeolite method?

It involves ion exchange where calcium and magnesium ions are replaced with sodium ions.

Define Alkalinity.

Alkalinity is the capacity of water to neutralize acids, often measured in terms of bicarbonate.

What is the ion exchange process for softening water?

A method where hard ions are replaced with sodium ions using resin materials.

What is the significance of scales and sludges in water systems?

They can lead to inefficiencies and damage in boilers and pipelines.

What is boiler corrosion?

Corrosion related to the environment within the boiler and its chemical properties.

Discuss the lime soda process for softening hard water.

This process involves adding lime and soda ash to precipitate calcium and magnesium.

What is caustic embrittlement and how can it be prevented?

Prevented by controlling caustic concentrations and using proper materials.

Describe the iron exchange process used for softening water.

The process uses ion exchange resins to remove hardness by replacing hard ions.

Explain how potable water is disinfected by ozonation.

Ozone gas is used to kill bacteria and viruses in water, effectively disinfecting it.

What is the significance of the flash point in lubricating oils?

It indicates the temperature at which vapors can ignite, affecting safety and usability.

Define lubricant and its functions.

Lubricants reduce friction and wear between surfaces, enhancing efficiency and performance.

What are the important properties of lubricating oils?

Viscosity, flash point, pour point, thermal stability, and oxidation resistance.

Describe hydrodynamic lubrication. What is its significance?

A lubrication mechanism where a fluid film separates moving surfaces, reducing wear.

What are living polymers?

Polymers that can undergo further polymerization without losing their original properties.

What is the principle behind Beer-Lambert's law?

It relates the absorption of light to the properties of the material through which the light is traveling.

Differentiate between thermoplastic and thermosetting polymers.

Thermoplastics can be remolded, while thermosets become permanently hard after curing.

What is vulcanization of rubber?

A chemical process that involves the cross-linking of rubber molecules to enhance durability.

Define Corrosion.

The deterioration of materials, usually metals, due to chemical reactions in their environment.

Explain electrochemical corrosion.

A type of corrosion that involves an electrochemical process, often in the presence of moisture.

What are the parameters related to ultimate analysis of fuels?

Carbon, hydrogen, nitrogen, sulfur, and ash content determine fuel quality.

What is the significance of calorific value in fuels?

It indicates the energy content of a fuel and its efficiency for combustion.

What is the difference between NCV and GCV?

NCV (Net Calorific Value) excludes the heat of vaporization of water, while GCV (Gross Calorific Value) includes it.

Explain the phase rule in thermodynamics.

The phase rule defines the number of degrees of freedom in a chemical system based on phases.

What are electronic transitions in spectroscopy?

Transitions of electrons between energy levels in atoms or molecules during photon absorption.

What is U.V. Spectroscopy?

A technique that uses ultraviolet light to analyze substances based on their absorption properties.

What is the significance of IR spectroscopy?

It provides insights into molecular structures and functional groups based on vibrational transitions.

Describe atomic size trends in the periodic table.

Atomic size generally decreases across a period and increases down a group due to electron shielding.

What is electron affinity?

The energy change that occurs when an electron is added to a neutral atom.

Define ionization energy.

The energy required to remove an electron from an atom in the gaseous state.

What are the categories of polymers based on molecular structure?

Polymers can be classified as linear, branched, and cross-linked.

What is the role of coefficients in chemical reactions?

They represent the ratio of moles of reactants and products in a balanced equation.

What are the factors affecting periodic trends?

Nuclear charge, electron shielding, and atomic structure influence periodic trends.