When zinc reacts with HCl or NaOH , 2 common things are seen:
1.  Hydrogen gas is evolved which is neutral to litmus.
2.  A soluble salt is formed.
Since zinc is an amphoteric metal , these products are formed.
(Amphoteric- A metal which reacts with both acids and bases to give salt and hydrogen.The amphoteric metals are Zn, Al,Pb , Sn and Be)
Zn+2HCl=ZnCl _{2} +H _{2}
Zn+2NaOH=Na _{2} ZnO _{2} +H _{2}
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