How much hydrogen will be released when zinc is dissolved in 45 g of 3% hydrochloric acid solution?

First, we write down the equation of reactions.
Zn + 2HCL = ZnCl2 + H2.
First, we find the mass of hydrochloric acid. For this we use the following formula.
W = mr.w / mr-ra × 100%.
mr.v. = W × mr-pa / 100% = 3 × 45/100 = 1.35 g.
Next, we find the amount of perchloric acid substance.
n = m / M.
n = 1.35 / 36.5 = 0.04 mol.
Further, according to the reaction equation, we find the amount of hydrogen substance.
0.04 mol HCL – x mol H2.
2 mol HCL – 1 mol H2.
Find the unknown value of x.
X = 0.04 × 1 ÷ 2 = 0.02 mol H2.
Next, we find the volume of hydrogen.
V = n × Vm = 0.02 mol × 22.4 L / mol = 0.448 L.
Answer: V (H2) = 0.448 l.