which of the following reaction can give hydrogen gas.

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(1)Zn + conc.H2SO4

(2)Cu + dil. H2SO4

(3)Mn + very dilute HNO3

(4)pb + dil HNO3

 

Plzzzz explain all options....Thanks!!

Zinc reacts with sulphuric acid to form metal sulphate and hydrogen gas.

 

 Zn + H₂SO₄ → ZnSO₄ + H₂ ↑

 

And Copper does not reacts with the dilute H₂SO₄ 

 

And

 

Metals also react with nitric acid, but hydrogen gas is not evolved, because nitric acid is a strong oxidising agent. So, it oxidises the hydrogen to water and itself gets reduced to any nitrogen oxide.

However, magnesium and manganese react with very dilute nitric acid to evolve hydrogen gas.

 

Mg + 2HNO₃ → Mg(NO₃)₂ + H₂ ↑

Mn + 6HNO₃ → Mn(NO₃)₂ + H₂ ↑

 

When Lead reacts with dilute HNO₃ gives redox reaction but no hydrogen gas is evolved as a product.

 

Pb + HNO₃ → Pb(NO₃)₂ + NO + H₂O

Hence the correct options are A and C.