A. To check its Acidity and Basicity
B. To Check temperature
C. To check its Purity and nature
D. None of These
¨ How does boiling point decrease if impurities are added? When a pure substance boils, the vapor pressure of the liquid equals the atmospheric pressure around it. However, if impurities are added to the liquid, the vapor pressure of the liquid decreases. This happens because the impurities disrupt the attractive forces between the liquid molecules, making it harder for the molecules to escape into the gas phase. As a result, the liquid requires less thermal energy to vaporize, and the boiling point decreases.
¨ An example of this is saltwater. When salt is added to water, the boiling point of the water decreases. This is why it takes longer to cook food in saltwater than in pure water, because the lower boiling point means the water is not as hot.
¨ Food will not be fully cooked at higher altitudes and needs more energy because as high altitudes atmospheric pressure decreases as a result Boiling point decreases and food takes more time so we use pressure cooker to cook food readily.
¨ How does water density decrease at 0 degrees and reach a maximum at 4 degrees? The density of water decreases at 0 degrees Celsius because as the temperature decreases, the water molecules begin to form a crystalline structure (ice), which is less dense than liquid water. As the temperature continues to decrease, more and more water molecules arrange themselves into the rigid lattice structure of ice, causing the density of the remaining liquid water to decrease.
¨ However, at 4 degrees Celsius, the density of water reaches a maximum. This happens because the water molecules are packed together most closely at this temperature, due to a combination of hydrogen bonding and molecular motion. As the temperature either increases or decreases from 4 degrees Celsius, the hydrogen bonds between water molecules begin to weaken, causing the molecules to move further apart and decreasing the density of the water.
Submitted by :- Jamil Ahmed