1st Year Chemistry Chapter 4 Notes

• Important Fill in the blanks of Chapter Number 4: Liquids and Solids of First-year Chemistry
• Intermolecular forces are weaker than interamolecular forces why?
• What are London Dispersion forces?
• Write down two applications of hydrogen bonding.
• The density of ice is less than liquid water. Explain with reason.
• Ice floats on H2O. Give reason.
• Water is liquid at room temperature while H2S is a gas. Comment?
• Describe the importance of vacuum distillation.
• Why HF is a weaker acid than HCI?
• Define dipole-dipole forces with an example. OR Describe the solubility of hydrogen-bonded molecules.
• What is the role of Hydrogen Bonding in Biological Compounds?
• Define hydrogen bonding and give one example.
• Describe the cleaning action of soaps and detergents on the basis of H-bonding.
• What type of intermolecular forces will dominate in the following liquid? (a) CH3COCHз (propanone) (b) C8H18 (Octane)
• Define vapour pressure. Write down two factors that effect vapour pressure of a liquid?
• Why the heat of vapourization of water is greater than that of CH4?
• Water freezes from surface to downward direction in ponds and lakes. Explain it?
• Earthenware vessels keep water cool. Explain?
• Evaporation causes cooling. Justify it?
  
• Why do we feel a cooling affect after taking a bath?
• Justify that evaporation take place at all temperatures? 
• What is evaporation? How does it cause cooling?
• Name the factors which affect the London forces.
• What is meant by geometrical shape of solid?
• What is role of hydrogen bonding in paints, dyes, and textile materials?
• Define Evaporation. Name the factors which effect Evaporation.
• Define boiling point.
• Why different liquids possess different boiling points? 
• The boiling point of water is different at Murree hills and at Mount Everest. How?
• Vacuum distillation can be used to avoid decomposition of sensitive liquid, Why?
• The vapour pressure of diethyl ether is higher than that of water at same temperature. Give reason?
• Why the values of boiling points of noble gases increases from top to bottom within a group?
• Why the temperature of a boiling liquid does not rise even if heat is continuously supplied to it?
• Explain the working of pressure cooker?
• How the increase of polarizability down the group in noble gases is responsible for increase in melting and boiling points?
• Explain why the melting points, boiling points heat of vaporization and heat of sublimations of electrovalent compounds are higher than covalent compound?
• Why boiling point of water varies from sea-level to higher places?
• How liquid crystals act as temperature sensors? 
• Give two important uses of liquid crystals?
• What do you mean by solvent extraction? Which law controls it?
• Transition temperature is the term used for elements as well as compounds. Explain?
• Differentiate between an amorphous solid and crystalline solid?
• Why amorphous solids like glass are also called super cooled liquids?
• Ionic compounds do not show the phenomenone of isomerism. Why?
• Why sodium is softer than copper but both are good conductors of electricity?
• Ionic solids are insulators in solids state, but become conductors when dissolved in water. Explain?
• Explain why sodium chloride and cesium chloride have different structures.
• Ionic solids do not conduct electricity in solid state. Give reason.
• What is Lattice and Lattice energy?
• Graphite is conductor but diamond is insulator. Give reason?
• How is dynamic equilibrium established during evaporation of a liquid in a closed vessel at contant temperature? 
•  How are liquid crystals used to locate veins, arteries infections and tumors?
• Lower alcohols are soluble in water but hydrocarbons are insoluble. Give reason. OR Why ethyl alcohol is soluble in water? OR Why water and ethanol can mix easily and in all proportions.
• Why vapour pressure of CCl4 is 87 torr while isopentane is 580 torr at 20 °C?
• Why ice occupies 9% more volume than liquid water.
• Why heat of sublimation of iodine is very high than other halogens.
• Lower alcohols are soluble in H2O but hydrocarbons are insoluble. Give reason.
• Boiling points of halogens increase down the group. Give reason.
• Give reason for lowest boiling point of hydrides of group IV A elements.
• Ethane and hexane has Boiling Points, -88.6°C and 68.7°C respectively. Comment on it.
• What is role of hydrogen bonding in paints, dyes, and textile materials?
• Explain that Vapour pressures of Solids are far less than those of liquids?
• Why heat of sublimation is greater than heat of vapourization?
• How vapour pressure is related to intermolecular forces of attraction?
• The crystals showing isomorphism mostly have the same atomic ratios; explain.
• And many more Short Questions with Answers .....
• What is H-bonding? Discuss H-bonding in biological compounds.
• Define vapour pressure. 'Write down manomatric method for its diagram.
• Define liquid crystals. Discuss important uses of liquid crystal. 
• Define Hydrogen bonding. Explain any three applications of H-bonding.
• What are ionic solids? Give three properties of ionic solids.
• What are covalent solids? Discuss their properties in detail.
• What are molecular solids? What types of forces are present in them? Write down their properties.