Q.1. Name the reaction in which one of the reacting species losses while the other gains electrons.
Q.2. C2H5OH(l) + 3O2 --------> 2CO2(g) + 3H2O(l) ---- IS THIS REACTION EXO THERMIC OR ENDOTHERMIC. WHY?
Q.3. Why do gold & silver not corrodein moist air?
Q.1. Name the reaction in which one of the reacting species losses while the other gains electrons.
Q.2. C2H5OH(l) + 3O2 --------> 2CO2(g) + 3H2O(l) ---- IS THIS REACTION EXO THERMIC OR ENDOTHERMIC. WHY?
Q.3. Why do gold & silver not corrodein moist air?
Q.1. This is called Redox reaction. It is a chemical reaction which involves addition of hydrogen (loss of electrons) or removal of oxygen or gain of electron(s) is called as reduction. A chemical reaction in which oxidation and reduction take place simultaneously is called redox reaction.
2Na + H2 → 2NaH (addition of hydrogen)
Fe3+ + e- →Fe2+ (gain of electron)
Q.2. This is an exothermic reaction. Because this reaction involves the combustion of C2H5OH releasing heat. The reaction is as follows:
C2H5OH (l) + 3O2 (g) -----> 2CO2 (g) + 3H2O (l)
The heat of combustion of ethanol is -1368 kJ/mol. Total enthalpy change = total heat of formation of CO2 reaction + total heat of formation of H2O in reaction.
Q.3. Gold and silver do not corrode in moist air because they do not react with water and oxygen of moist air. But silver very very slowly react to moist air forming thin black oxide layer.
Q.1. This is called Redox reaction. It is a chemical reaction which involves addition of hydrogen (loss of electrons) or removal of oxygen or gain of electron(s) is called as reduction. A chemical reaction in which oxidation and reduction take place simultaneously is called redox reaction.
2Na + H2 → 2NaH (addition of hydrogen)
Fe3+ + e- →Fe2+ (gain of electron)
Q.2. This is an exothermic reaction. Because this reaction involves the combustion of C2H5OH releasing heat. The reaction is as follows:
C2H5OH (l) + 3O2 (g) -----> 2CO2 (g) + 3H2O (l)
The heat of combustion of ethanol is -1368 kJ/mol. Total enthalpy change = total heat of formation of CO2 reaction + total heat of formation of H2O in reaction.
Q.3. Gold and silver do not corrode in moist air because they do not react with water and oxygen of moist air. But silver very very slowly react to moist air forming thin black oxide layer.
