Question

4. Which of these metals cannot be used to prepare hydrogen by the action of an acid?
a, sodium
b, iron
e, calcium
d , copper
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Answer 1

Answer:

Copper

Explanation:

In the reactivity series of metal copper is less reative than hydrogen  

Answer 2

Copper

Explanation:

We know that metals react with dilute acids to form metal salt and hydrogen gas. However, only those metals which are more reactive than hydrogen and so placed above hydrogen in the activity series give this reaction. Since copper is less reactive than hydrogen, it is not able to displace hydrogen from dilute acids