Chemical reaction Interview Questions & Answers

Question 1. Why Should A Magnesium Ribbon Be Cleaned Before Burning In Air?

Answer :

Magnesium ribbon is cleaned before burning to remove the coating of imprities such as oxide so that reaction takes place properly.

Question 2. Why Is Double The Amount Of Gas Collected In One Of The Test Tubes In Electrolysis Of Water Than Th Amount Collected In The Other? Name This Gas?

Answer :

On electrolysis of water, it decomposes to give hydrogen and oxygen.

          2H₂O – 2H₂ + O₂

This, water decomposes to give hydrogen and oxygen in the ratio of 2:1 so, The double amount of hydrogen is collected in one test tube as compore to oxygen in other test tube.

Question 3. Why Should Chemical Equation Be Balanced?

Answer :

According to cow of conservation of mass, the total mass of reactant is equal to the mass of product This is possible only it the number of atoms of each element is equal on two sides of equation So, a chemical equation should be balanced.

Question 4. Why Is Respiration Considered As An Exothermic Reaction? Explain?

Answer :

During respiration digested carbohydrate as glucose combines with oxygen to release energy which is utilized by our body.

It is considered exothermic reactions.

Question 5. Why Are Decomposition Reactions Called The Opposite Of Combination Reactions?

Answer :

In a decomposition reaction a single substance splits to form two or more than two substances, where as, in combination reaction two or more substances combine to form a single substance So, it is opposite to each others.

Question 6. A Shiny Brown Colored Element ‘x’ On Heating In Air Becomes Black In Cooler Name The Element ‘x’and Black Colored Compound Formed?

Answer :

The element X is copper. Black colored compound is copper oxide.

Question 7. Why Do We Apply On Iron Articles?

Answer :

Iron articles are applied by paints so that air cannot come in direct contact with iron. As a result it prevents rusting.

Question 8. Oil And Fat Containing Food Items Are Flushed With Nitrogen. Why?

Answer :

In the presence of oxygen fatty food are oxidized to compound and becomes rancid. Flushing with nitrogen cut off oxygen and protects the food from rancidity.

Question 9. What Is Entropy?

Answer :

Entropy is a measure of disorderliness. It explains the system's closeness to equilibrium.

Question 10. What Is Gibbs Free Energy?

Answer :

It is the available energy or the greatest amount of mechanical work done by a system at constant temperature and pressure.

Question 11. At What Temperature Does Water Have Maximum Density?

Answer :

At 4 deg C the density of water is 1000 kg/cu.m.

Question 12. What Is An Isochoric Process?

Answer :

It is a thermodynamic process at constant volume. Also called isovolumetric process.

Question 13. What Is A Cstr And What Are Its Basic Assumptions?

Answer :

Continuous Stirred tank Reactor. Assumptions are steady state, constant density, constant temperature, one irreversible first-order reaction.

Question 14. List The Advantages And Disadvantages Of A Pfr?

Answer :

Advantages: Continuous operation, high conversion rate, less cost for operation. Disadvantages: temperature gradients, high maintenance cost.

Question 15. Explain The Functioning Of A Three-way Catalytic Converter?

Answer :

Carbon monoxide oxidation, Nitrogen oxide reduction, uncombusted hydrocarbon oxidation.

Question 16. Explain Global Warming From A Common Man's And An Engineer's Perspective?

Answer :

In a common man's perspective, the increase in world temperatures is global warming. In an engineer's perspective, it is the average temperature increase in the surface temperature of the earth, mainly due to increased concentration of greenhouse gases. The greenhouse gases capture the heat radiated by the earth, inside the atmosphere, enabling the increase in temperature.

Question 17. What Is Carbon Sequestration?

Answer :

A technique for capturing carbon dioxide for a long term in order to reduce its effects on global warming.

Question 18. What Are The Greenhouse Gases In Earth's Atmosphere?

Answer :

Water vapor, carbon dioxide, ozone, methane, nitrous oxide and CFC.

Question 19. Define Octane Number?

Answer :

It is the resistance to detonation of a fuel in a spark ignition engine compared to the isooctane-n-heptane mixture.

Question 20. Explain The Working Of A Spray Condenser?

Answer :

A spray condenser is used for the condensation of humid water vapor by direct contact with water. The inlet water is at a temperature less than the dew point of air in the chamber.

Question 21. How Does A Cyclone Separator Work?

Answer :

It works as gas-solid separation equipment using vortex formation.

Question 22. Define Viscosity?

Answer :

Viscosity is a measure of a fluid's resistance to shear stress.

Question 23. What Is Critical Radius Of Insulation?

Answer :

The critical radius of insulation is the thickness of an insulation that does not affect the convection resistance. It is the ratio of the thermal conductivity of the insulator to the convection heat transfer coefficient.

Question 24. What Is A Black Body?

Answer :

An ideal object that absorbs all electromagnetic radiations.