Chemistry
State why hydrogen is not prepared in the laboratory by the action of –
(a) Sodium with cold water.
(b) Calcium with dilute sulphuric acid.
(c) Lead with dilute hydrochloric acid.
Hydrogen
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Answer
(a) Sodium is very reactive and reacts with water violently. It melts into a globule and darts about in water. Hence, the collection of hydrogen is difficult using sodium and cold water.
(b) As the reaction between calcium and dil. sulphuric acid is highly explosive and practically not feasible, hence, hydrogen is not prepared in the laboratory by the action of calcium with dilute sulphuric acid.
(c) Lead reacts with dilute hydrochloric acid forming an insoluble coating of lead chloride (PbCl2) and hence, further reaction comes to a stop. Therefore, hydrogen is not prepared in the laboratory by the action of lead with dilute hydrochloric acid.
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