At higher altitudes, the atmospheric pressure decreases. Atmospheric pressure exerts pressure on the molecules of the liquid, confining them. In order to boil, the electrons must be excited, but must become hotter to overcome the pressure of the atmosphere. Therefore, pressure makes a liquid boil at a higher temperature. At Shimla, water actually boils at a faster rate, but it takes longer to cook vegetables. So, it is recommended to add salt in water, which decreases the boiling point of water, to cook the vegetables.

Statement (1) is correct. Froth flotation is one of the processes used to recycled paper. In the paper industry this step is called deinking or just flotation. The target is to release and remove the hydrophobic contaminants from the recycled paper. The contaminants are mostly printing ink and stickies. Statement (2) is correct. Distillation is the process of heating a liquid to its boiling point, capturing and cooling. Extraction of petroleum, diesel, naphthalene and bitumen is the example of fractional distillation.

Statement (1) is correct. Solid carbon dioxide is used in theaters to give special effects.

Statement (1) is correct. When an open bottle of scent is kept in a corner of the room, its odour is felt in all the corners. This is due to the phenomenon of diffusion. The movement of particles from its higher concentration to its lower concentration is called diffusion. Statement (2) is incorrect. Sublimation is the transition of a substance directly from the solid phase to the gas phase without passing through an intermediate liquid phase.

Statement 1 is correct. The temperature of hot food is more. Therefore, the particles of hot vapours coming out of hot sizzling food have higher kinetic energy, i.e. they move faster and hence, the smell of hot sizzling food reaches several metres away. Statement 2 is incorrect. A body with black and rough surface absorbs heat most rapidly (it absorbs heat energy).

Statement (1) is correct. The molecules of solids have the maximum force of attraction among them. For the conversion of solid into liquid, the given heat is used to break the strong bonds between them. Statement (2) is also correct. Iron rod is heavier because the space between the particles of iron is very less, comparatively to the space between the particles of chalk.

The correct reason for the condensation of water droplets at the outer surface of glass containing cold water is the loss of KE of water molecules, when come in contact with cold surface.

When solid melts into liquid, the speed of vibrating particles increases which results in Kinetic Energy of particles. The temperature remains the same.

Statement (1) is correct. The flooding of rice field cuts off the oxygen supply from the atmosphere to the soil that results in anaerobic fermentation of soil organic matter. Methane is a major end product of anaerobic fermentation. It is released from submerged soils to the atmosphere by diffusion and ebullition and through roots and stems of rice plants. Statement (2) is incorrect. The Kyoto protocol is the proposal to reduce Carbon Dioxide, and the Montreal protocol is to reduce the Chlorofluorocarbons to protect the ozone layer.

Statement (1) is correct. At higher altitudes, nose bleeding occurs because at higher altitudes, the atmospheric pressure decreases as a result the blood vessels of nose burst and cause bleeding. Statement (2) is correct. Sublimation is the process of conversion of solid directly into gaseous state. Therefore, Naphthalene balls disappear with time without leaving any solid.

Statement (i) is correct. Gases have high diffusing capability as compared to solid and liquid forms. Statement (ii) is correct. Gases have high KE due to large intermolecular spaces.

(a) With the increase in pressure, the water molecules come closer to each other and solidify. (b) With increase in surface tension of water, it leads to freezing by compressing the molecules of water.