Question:
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.
Solution:
1 mol of gas occupies = 22.7L Volume at STP atomic mass of Zn = 65.3u
From the above equation,
65.3g of Zn when reacts with HCl produces = 22.7L H2 at STP
Therefore, 32.65g of Zn when reacts with HCl will produce = 22.7 * 32.65/65.3 =11.35L of H2 at STP