Question

Question 1. Name two elements which produce hydrogen gas by treating with cold water write balanced chemical equation also.

Question 2. Give reason:

1. Lead metal is not used for the preparation of hydrogen gas

2. Dilute nitric acid is not used in the preparation of hydrogen gas

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Answer 1

Answer:

sorry I don't answer of this question

Answer 2

Answer:

Question 1.

Reactive metals like potassium and sodium react with cold water forming their corresponding hydroxides and evolving hydrogen. Their reactions are exothermic.

2K + 2H2O --> 2KOH + H2

2Na + 2H2O --> 2NaOH + H2

Question 2.

1) Lead metal is not used for preparation of hydrogen gas as lead reacts with dilute sulphuric acid or hydrochloric acid and forms an insoluble coating of lead sulphate or lead chloride. Therefore, further reaction is prevented.

2) Nitric acid, even in its dilute form, is not used in preparation of hydrogen from metals because:

Nitric acid is a powerful oxidizing agent, and the

oxygen formed due to its decomposition oxidizes the

hydrogen to give water, thus defeating the purpose of

the reaction.

3Zn + 8HNO3 --> 3Zn(NO3)2 + 4H2O + 2 NO

Hope it helps!!