Write the 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.
[Gram molar volume is 22.4 liters at S.T.P., Avogadro's number is `6.023xx10^(23)`]

Explanation

`Zn_2HCl rarr ZnCl_(2)+H_(2)`
In the reaction 2 moles of HCl produce 1 mole of `H_(2)`.
If 1 mole of HCl participate in reaction, `1//2` mole of hydrogen will be produced.
1 mole of `H_(2)` gas contains `6.023xx10^(23)` molecules at STP.
Number of molecules in `1//2` mole of `H_(2)` gas = `6.023xx10^(23)xx1..2=3.011xx10^(23)`