Question

Hots Questions : Think and answer. A bottle contains either salt to chalk. How will you find out what it has, without tastion it? Think and write how you will separate a mixture of water, sand, salt and iron filings. You may have to use a method not given in the chapter to separate sand and iron filings. Think -- which property of iron can be used for this? A mixture of salt and sugar is prepared by grinding then together. Do the molecules of the salt and sugar undergo any change? A Saturated solution of sugar in water is prepared. The temperature of water is lowered by 5 0 C. Will the solution continue to be saturated ? Give reasons. Sea water has salt dissolved in it. You know that pure water can be obtained from sea water by distillation. However, this method is not used to get drinking water from sea water. What do you think is the reason?

Answer 1

1.Pour water in the bottle and stir it. If the material dissolves completely, it is salt otherwise chalk.
2.Magnetic property of iron will be used. Bring a magnet close to the mixture to separate the iron fillings. The filter the mixture using filter paper to remove sand. Now boil the remaining mixture. The water will evaporate leaving behind salt. Condense the water vapour to get water.
3.Grinding is a physical change so grinding them will only turn them into finer particles and will not change their molecular structure or the properties.
4.If the temperature of the saturated solution will be lowered, it will remain saturated but some of the solute will come out, because lowering the temperature lowers the saturation point of solvent.
5.Sea water is not distilled because it is a very costly process. Moreover, distilled water is harmful as contains no minerals and it can corrode the internal parts of our body.

Answer 2

Answer:

1. Here is your first answer