10th Chemistry Some Important CBSE BOARD Question solution Q. An aluminium can is used to store ferrous sulphate solution. It is observed that in a few days holes appeared in the can. Explain the cause for this observation and write chemical equation to support your answer Ans: Reactivity of aluminium is far mor than iron(Fe). Because of high reactivity aluminium displaces iron from its sulphate solution and made its sulphate sulution i.e. , aluminium sulphate. and thats why holes appeared. 2Al + 3FeSO4 = Al2(SO4)3 +3 Fe Q. What do you mean by the term hydrated salt? Give two examples of hydrated salts which are white and state their chemical formula. Why is tooth paste used for cleaning teeth? Ans: Hydrated salts are those salts which contains some water of crystallization. For example: MgSO4.7H2O,SnCl2.2H2O When we wake up at morning our mouth contains sliva of pH=4.1(acidic) due to presence of more lactic acid, which can decay our teeth so we use toothpaste which contains some alkal...