PGT Chemistry Interview Questions and Answers

Galvanic cells convert chemical energy into electrical energy, while electrolytic cells convert electrical energy into chemical energy.

• Galvanic cells are spontaneous and produce electrical energy through a redox reaction

• Electrolytic cells are non-spontaneous and require an external source of electrical energy to drive a non-spontaneous redox reaction

• Galvanic cells have a positive cell potential, while electrolytic cells have a negative cell potential

• Examples of galvanic cells...read more

Mole concept is a fundamental concept in chemistry that relates the mass of a substance to the number of particles it contains.

• Mole is a unit of measurement used to express the amount of a substance.

• One mole of a substance contains Avogadro's number of particles (6.02 x 10^23).

• Molar mass is the mass of one mole of a substance.

• Mole concept is used in stoichiometry to calculate the amount of reactants and products in a chemical reaction.

• Example: 1 mole of carbon atoms has a mas...read more

Displacement reaction involves the replacement of an element in a compound by another element.

• A more reactive element displaces a less reactive element from its compound.

• The displaced element forms a new compound with the displacing element.

• The reaction can be represented by a chemical equation.

• Example: Zn + CuSO4 -> Cu + ZnSO4

• In this reaction, zinc displaces copper from copper sulfate to form zinc sulfate and copper.

Nucleophilic substitution is a reaction where a nucleophile replaces a leaving group from a molecule.

• Occurs in polar solvents

• Involves attack of nucleophile on electrophilic carbon

• Leaving group departs with a pair of electrons

• Can be SN1 or SN2 mechanism

• Examples include hydrolysis of alkyl halides and esters

The symbol of mercury is Hg.

• Hg is derived from the Latin word hydrargyrum which means liquid silver.

• It is a heavy, silvery-white metal that is liquid at room temperature.

• Mercury is commonly used in thermometers, barometers, and fluorescent lights.