Question

Why magnesium is not use as the laboratory preparastion of hydrogen

Answer 1

Dilute HNO3, being a very strong oxidizing agent, will not liberate hydrogen with metals, but water, except the metal is magnesium. Therefore, dilute HNO3 is not used for hydrogen preparation. To prepare hydrogen in the laboratory, metals like Na and K are not used because their reactions with mineral acids are too violent (although hydrogen is produced).
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