States of Matter

Correct Answer: Only I

Evaporation is the process by which water is converted from its liquid form to its vapour form and thus transferred from land and water masses to the atmosphere. In nature, the sun heats the water in ponds, lakes, rivers or sea, and changes into vapour and rises in air. Here water is also disappeared because of evaporation.

Water is not only colourless and odourless, it is tasteless too. 

Condensation is the change of the physical state of matter from gaseous phase into liquid phase. The temperature of the ice cold water is close to zero. The air around the container consists of water vapour, which accounts to humidity. When the water vapour comes in contact with the outer surface of glass containing ice cold water, there is a change in physical state of water vapour to water in liquid phase due to lower temperature and condensation. Hence,  it accounts for the water droplets on the outer surface of a tumbler or a glass containing ice cold water.

At - 8 degree Celsius temperature, the water in Dal lake goes below the freezing point as the freezing point is 0 degree Celsius. So, the water in Dal lake will freeze and the lake will become so hard so that any body can walk and play on that.

Matter in the gaseous state has both variable volume and shape adapting both to fit its container. Its particles are neither close together nor fixed in place. For example, oxygen, carbon dioxide, steam, etc.

Acetic acid is not a mixture. It is a compound.

Alcohol in water forms a homogeneous mixture. All others are heterogeneous mixtures.

Starch has carbon, hydrogen and oxygen as its constituents. Option (1) is the property of carbon. Option (2) is the property of oxygen and hydrogen. Option (3) is the property of sugar, not its constituents. Option (4) is the property of oxygen and hydrogen.

Charcoal and sulphur form a heterogeneous mixture.

Potable water should not be full of micro-organisms. It should be free of micro-organisms.

Matter generally exists in three states; solid, liquid and gas. In solids, the particles are very close to each other and they have very strong inter-particle forces of attraction between them. 

Option (3) is correct.

100^oC is the boiling point of water, i.e. it is the temperature at which liquid starts boiling at the atmospheric pressure. Therefore, at this temperature both liquid and gaseous states of water can co–exist. Once boiling point is reached, the temperature of the system will remain constant until all water changes to gaseous state because the heat supplied is used to overcome the forces of attraction between particles of water so as to change it into gaseous state. At 99^oC, water will exist in liquid and at 101^oC, water will exist in gaseous state. At 0^oC (i.e. Melting point of ice) both ice and water will co-exist as at this temperature, ice starts melting. The heat supplied is used to overcome the forces of attraction between the particles so as to convert it into liquid state. The temperature will remain 0^oC until all the ice changes into liquid and therefore, at 0^oC, both solid and liquid states will co-exist.

When we pour some acetone (nail polish remover) on our palm, we feel cool. This is because particles gain energy (equal to latent heat of vapourisation) from our palm or surroundings and evaporate, causing the palm to feel cool. the palm will not get heated. It will not become red and it will not pain as nail polish remover does not harm our skin.