Question

A mixture of iron filings and sulphur powder is divided into two parts and given to

two students A and B respectively. Student A heated the mixture strongly and then

added the following reagents while Student B added the following reagents directly to

the sample provided. The reagents are: a) Dil. HCl b) Carbon disulphide. Mention the

difference in the observations of A and B in both the cases.​

Answer 1

Observation is given below

Explanation:

• When iron filings and Sulphur are mixed together , FeS is formed .
• Now when 'A' heated the mixture and added 2 reagents , following observation was made :

       Dilute HCl reacts with FeS to form $H_2S$ gas that smells like rotten eggs and turns lead acetate black.

          $FeS + 2 HCl (dil) \rightarrow H_2S + FeCl_2$

• When student 'B' carries put the same reaction without heating , iron filings and Sulphur mixture forms a gas . When a burning matchstick is brought near the gas , a pop sound is produced.

         $FeS + 2 HCl (dil) \rightarrow H_2 (g) + FeCl_2$