2 mL of sodium hydroxide solution is added to a few pieces of granulated 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 dilulte solution of strong acid.

Explanation

When sodium hydroxide solution is heated with granulated zinc metal, then Sodium zincate and hydrogen gas are formed
`underset("Sodium Hydroxide")(2NaOH (aq)) + underset("Zinc")(Zn(s)) overset("Heat")(rarr) underset("Sodium Zincate")(Na_(2)ZnO_(2)(aq)) + underset("Hydrogen")(H_(2)(g))`
Test for hydrogen . A splient is lit and held near the opening of the tube, then the stopper is removed to expose the splinet to the gas. If the gas is flammable the mixture ignites. This test is most commonly used to identify hydrogen which burns with a pop sound.
`underset("Zinc")(Zn(s)) + underset("Sulphuric Acid")(H_(2)SO_(4)(aq)) overset("Heat")rarr underset("Zinc Sulphate")(ZnSO_(4)(aq)) + underset("Hydrogen")(H_(2)(g))`