Question

Hydrogen is evolved by the action of cold dil. HNO3 on :

• A. Fe
• B. Mn
• C. Cu
• D. Al

Answer 1

Answer: (B)

Mn

Answer 2

(1) 4Fe  + 10 HNO3$\longrightarrow$ 4Fe (NO3)2 + NH4NO3 + 3H2O

very dil.

4Fe  +  10 HNO3 $\longrightarrow$ 4Fe(NO3)2  +  N2O  +  5H2O

     dil.

(2) Mn  +  2HNO3 $\longrightarrow$ Mn(NO3)2  +  H2

     dil.

(3) 3Cu  +  8HNO3 $\longrightarrow$ 3Cu(NO3)2  +  2NO  +  4H2O

     dil.

(4) 2Al  +  8HNO3 $\longrightarrow$ 2Al(NO3)3  +  2NO  +  4H2O