Question

what would happen if some amount of sodium hydroxide is added to zinc and the test tube is heated :
(a) Same amount of H2 gas is evolved
(b) H, gas is not evolved
(c) The amount of H, gas evolved is much less
(d) In place of H, gas, O2 gas evolves​

Answer 1

Answer: (a) some amount of H2 gas is evolved.

In general, metal do not react with bases to give salt and hydrogen gas, but there are some exceptions like Zn, Al etc.

Zn will react with sodium hydroxide to form a salt, sodium zincate and evolve hydrogen gas.

The equation for this reaction is:

$\sf \: Zn + NaOH \rightarrow Na _2ZnO_2 +\red{\boxed{ H_2\uparrow}}$