Ch 8 Chemistry Class 11 Notes

• What is meant by the stage of chemical equilibrium?
• Define reversible reaction. Give an example.
• Define irreversible reaction. Give an example.
• Justify that chemical equilibrium is dynamic in nature: In reversible chemical reactions the molecules of reactants collide and convert into products. At the same time the molecules of the products are converting into reactants. When two opposing forces maintain the equal rates then equilibrium is there and that is dynamic equilibrium in nature.
• Why the equilibrium constant value has its units for some of the reversible reactions but has no units for some other reactions?
• When four types of chemical equilibrium constants for a reaction become equal? How Kp and Kc are related?
• How the value of Kc helps to determine extent of reaction?
• What happens to the direction of a reversible reaction when the ratio of the concentrations is less than actual Kc?
• The change of volume disturbs the equilibrium position for some of the gaseous phase reactions but not the equilibrium constant. Why?
• Why are the exothermic reactions favored to the forward direction by cooling, but reverse is true for endothermic reactions?
• The change of temperature disturbs the equilibrium position and the equilibrium constant of reaction. Justify.
• What will be effect of change in pressure on NH3 and SO3 synthesis?
• how does a catalyst affect a reversible reaction?
• How NaCl can be purified by common ion effect?
• Define common ion effect. Give an example.
• What is the effect of common ion on solubility?
• Why the ionic product of water increases with the increase of temperature?
• What is percentage ionization of acid?
• Define pH and pOH. Give mathematical expression.
• what are the types of buffers? 
• Why do we need buffer solutions? OR What are the applications of buffers?
• The solubility of glucose in water is increased by increasing the temperature. Explain.
• Define solubility product. Give an example. 
• How solubility is determined from Ksp?
• what is the effect of common ion on solubility? The presence of a common ion decreases the solubility of a slightly soluble ionic compound. In order to explain it, consider a saturated solution of PbSO4, which is a sparingly soluble ionic salt.
• Write two applications of equilibrium constant?
• How change in volume disturbs the equilibrium position for some of the gas phase reactions but not the equilibrium constant?
• Why solid ice at 0°C can be melted by applying pressure without supply of heat from outside.
• Why do the rates of forward reactions slow down when a reversible reaction approaches the equilibrium stage?
• Reversible reaction attains the position of equilibrium which is dynamic in nature and not static. Explain it. 
• Mention the properties of chemical equilibrium. 
• What is the justification for the increase of ionic product with temperature?
• The change of volume disturbs the equilibrium position for some of the gaseous phase reactions but not the equilibrium constant. 
• When a graph is plotted between time on x-axis and the concentrations of reactants and products on y-axis for a reversible reaction, the curves become parallel to time axis at a certain stage.
• The rate of decreases of concentrations of any of the reactants and rate of increase of concentrations of any of the products may or may not be equal, for various types of reactions, before the equilibrium time. Explain it.