Question

2ml of sodium hydroxide solution is added to a few pieces of granuleted zinc metal taken in a test tube. When the contents are warmed, a gas evolves which is bubbled through a soap solution before testing. Write the equation of the chemical reaction involved and the test to detect the gas. Name the gas which will be evolved when the same metal reacts with dilute solution of a strong acid.

Answer 1

when sodium hydroxide reacts with zinc then it forms sodium zincate and hydrogen gas is released.
2NaOH+ Zn ➡ Na2ZnO2 + H2

when zinc reacts with hydrochloric acid again hydrogen gas will be evolved.
Zn + 2HCl ➡ ZnCl2 +H2

hope it helps you.