Few essential points in general science

There are few essential points while remembering general science. Below are few points (basically Chemistry) which I thought can be useful while preparing for competitive exams. It may look like you have already learnt but when it comes to exams, you may think ohhh ! say for example, "sodium bicarbonate" is also called cooking soda which is often confused with "sodium carbonate" the chemical name of baking soda.

Many of us tempt to forget the things and that too the easiest one. This list is just to give some common confused ones and a general terms in science. 

1.      A candle blows off when covered because it does not get oxygen which helps in burning.

2.      Phosphorus catches fire if kept in air but is unreactive with water, so it is kept in water.

3.      When sugar is heated above 200◦C, it decomposes into carbon and water and therefore gets charred.

4.      While making ice-cream, salt is mixed with ice to reduce freezing temperature from 0◦ to 5◦C. This helps to freeze the cream.

5.      Lactose content of milk undergoes fermentation and changes into lactic acid which on reaction with lactose forms curd.

6.      Zinc phosphide is used for killing rats and zinc chloride is used for coating furniture to prevent termites.

7.      Calcium hydride (CaH) is called hydrolith.

8.      In flash bulb, magnesium wire is kept in atmosphere of nitrogen gas.

9.      Barium sulphate is used in X-rays of abdomen as barium meal.

10.   Silver and copper are best conductor of electricity. Gold and silver are the most malleable metal.

11.   Iron pyrites (FeS₂) is known as fool’s gold.

12.   Zinc oxide (ZnO) is known as flower of zinc or Chinese white and is used as white paint.

13.   Silver spoon is not used in egg food as it turns black.

14.   Mercury is stored in iron pot.

15.   Radium is extracted from pitch blende.

16.   Phosphine gas is used in Holme’s signals.

17.   Sea weeds contains iodine. Bones contain 57% calcium phosphate.

18.   Artificial perfumes are prepared from ethyl acetate.

19.   Chlorine is used for the purification of water, for synthesis of bleaching powder etc.

I will come back with these type of confused and general terms in my next post.