Question

4. An element A reacts with gas B to produce compound C. An aqueous solution of C can change the color of red litmus paper into blue. The gas B in a mixture with other gases is used for welding metals. What is the nature of element A? ​

Answer 1

Answer:

A is calcium. It reacts with water to give calcium hydroxide. B is calcium hydroxide and is used for white washing. C is calcium oxide.  

The reactions are as follows:

Ca+2H  

2

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O→Ca(OH)  2 +H 2 Ca(OH)  2 →CaO+H  2 ​  +CaO+H  2  O→Ca(OH) 2

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Explanation: