Question

Write equation for the reaction of zinc with hydrochloric acid and balance the equation .Find out the number of molecules of hydrogen gas produced in this reaction,when 1 Mole of HCl completely reacts at S.T. P.?

Answer 1

The metal reacts with an acid to form salt and hydrogen gas.
$Zn\left(s\right)+2HCl\left(aq\right)⟶ZnC{l}_2\left(aq\right)+H_2\left(g\right)$
2 mole of HCl gives 1 mole of $H_2$
1 mole of HCl gives 0.5 mole of $H_2$
1 mole of $H_2$ gas = $6.022\times {10}^{23}molecules$
0.5 mole of $H_2$gas = $6.022\times {10}^{23}\times 0.5=3.011\times {10}^{23}molecules$