Pure distilled water (H2O):
1. does not conduct electricity
2. boils at a higher temperature when table salt is added to it
3. freezes at a lower temperature when table salt is added to it
4. good for health
Choose the correct option from the codes given below:
- does not conduct electricity.
This is an incorrect statement. Pure water is a poor conductor.
- boils at a higher temperature when table salt is added to it
This is a correct statement. As soon as any of the salt dissolves in the water, the boiling point of the water will begin to rise — by about one half degree Celsius for every 58 grams of salt dissolved per kilogram of water. In fact, any non-volatile soluble substance will raise the boiling point of water. That is why antifreeze (ethylene glycol) provides boiling protection in winter as it simultaneously provides
freezing protection in the summer.
- freezes at a lower temperature when table salt is added to it
This is a correct statement. When the temperature of salt water is lowered, the molecules within in will lose energy and hence come closer together to try to form the hydrogen bonding required for ice. However, as impurities (salt) are in the way, they need to lose more energy so as to create the necessary bonding. Hence the lower freezing point.
- good for health
This is not a correct statement. Pure water has no mineral and thus not good for health.
This question is a part of GKToday's Integrated IAS General Studies Module