Question

$H_2$ gas can not be prepared by :

• A. $Be$ $+$ $NaOH$
• B. $Na$ $+$ $NaOH$
• C. $Mg$ $+$ $NaOH$
• D. both A and B

Answer 1

The correct option is D both A and B

For (A):- $Be+NaOH⟶N{a}_{2}Be{O}_2+H_2$

For (B):- $Na+NaOH⟶N{a}_{2}O+H_2$

For (C):- $Mg+2NaOH⟶Mg(OH{)}_2+2Na$

From the above three reactions, it can be concluded that (A) and (B) react with $NaOH$ to give $H_2$ gas but (C) does not give $H_2$ gas.

Therefore, option D is correct.