Question

{Question}

1) A sample of water Boils at 102°C and has a salty taste.what do you conclude from this?
2} You are given sample of a white powdery substance.It may be the common salt or chalk powder.How you will identity without tasting it?
3} During the purification of water for city supply,the raw water from river/lake is allowed to stand undisturbed in large tanks. What happenes here ?
{There are 3 question }

Answer 1

1. No, the water is not pure. It is because, the boiling point of pure water is 100°C but the given sample boils at 102°C. It indicates that it has some dissolved impurities. No, the water will not freeze at 0°C. Instead it will freeze below 0°C as it has impurities dissolved in it.

2.

Following property can be used :

1. Dissolve salt and sugar separately in alcohol, sugar will be dissolved in it while salt will not be dissolved.

i) Heat these salts separately, sugar will melt readily while salt will not.

(iii) Dissolve these two separately in water. The salt solution will conduct electricity due to the presence of

Na

+

ion and Cl

−

ion while the sugar solution will be a non-conductor.

3. Sedimentation:

Water pumped from the source (river, lake or dam) is allowed to stand in large tanks, called settling tanks, for a few hours. Mud, sand and other suspended particles settle down. The addition of a small quantity of potash alum (K2SO4 . A12(SO4)3 . 24H2O) helps the suspended particles to settle down quickly.

Answer 2

Answer:

.1)) When a sample of water starts boiling at 102 degree Celsius and has a salty taste, it can be concluded that the sample of water is not pure. The water is considered impure because a sample of pure water holds the capacity to boil at 100 degree Celsius...

2)) Following property can be used :

1. Dissolve salt and sugar separately in alcohol, sugar will be dissolved in it while salt will not be dissolved.

i) Heat these salts separately, sugar will melt readily while salt will not.

(iii) Dissolve these two separately in water. The salt solution will conduct electricity due to the presence of Na+ ion Cl - ion

while the sugar solution will be a non-conductor.

3)) => Sedimentation:

Water pumped from the source (river, lake or dam) is allowed to stand in large tanks, called settling tanks, for a few hours. Mud, sand and other suspended particles settle down. The addition of a small quantity of potash alum (K2SO4 . A12(SO4)3 . 24H2O) helps the suspended particles to settle down quickly. The solid that settles at the bottom of the tank is called sediment. That is why these tanks are also called sedimentation tanks. The water over the sediment layer is more or less clean...

=> Filtration:

The water from the sedimentation tank is filtered through layers of sand and gravel. Filtration is also done through activated charcoal, which affords better-quality water. Activated charcoal is a special type of charcoal made by heating ordinary charcoal in vacuum. This charcoal holds the impurities strongly.

Hope you got your answer..