Hydrogen gas is prepared in the laboratory by reacting dilute HCl with granulated zinc. Following reaction takes place.

Zn + 2HCl → ZnCl₂ + H₂

Calculate the volume of hydrogen gas liberated at STP when 32.65 g of zinc reacts with HCl. 1 mol of a gas occupies 22.7 L volume at STP; atomic mass of Zn = 65.3 u.

 

Calculation:

1 mole of gas occupies = 22.7l volume at STP

Atomic mass of Zinc (Zn) = 65.3u

65.3g of Zn when reacts with HCl produces 22.7L H₂ at STP

Hence,

32.65g of Zinc when reacts with hydrochloric acid will produce 11.35L of H₂ at STP.