What volume of hydrogen gas at STP would be liberated by the action of 50 mL of dilute H_(2)SO_(4) of 40% purity and having a density of 1.3 g mL^(-1) on 20 g of zinc ? (Atomic mass of Zn = 65)

What volume of hydrogen gas at STP would be liberated by the action of

1.	What volume of hydrogen gas at STP would be liberated by the action of 50 mL of dilute H_(2)SO_(4) of 40% purity and having a density of 1.3 g mL^(-1) on 20 g of zinc ? (Atomic mass of Zn = 65)
Answer» Solution :Step I. Calculation of mass of pure `H_(2)SO_(4)` `"Mass of 50 mL of dilute "H_(2)SO_(4)="Volume "xx"DENSITY = (50 mL)"xx("1.3 g mL"^(-1))=65g` `"But 100 g of "H_(2)SO_(4)" contains pure "H_(2)SO_(4)=(40)/(100)xx65g=26g` Step II. Calculate of volume `H_(2)` EVOLVED at STP The reaction TAKING place is `underset("= 65 g")underset("1 mol")(Zn)+underset("=98 g")underset("1 mol")(H_(2)SO_(4))rarrZnSO_(4)+underset("= 22.4 L at STP")underset("1 mol")(H_(2))` Obviously, `H_(2)SO_(4)` is the limiting REAGENT `"(because 20 g of Zn requires "H_(2)SO_(4)=(98)/(65)xx20" = 30 g which is not present)"` `"98 g of "H_(2)SO_(4)" evolve "H_(2)="22.4 L at STP"` `therefore"26 g of "H_(2)SO_(4)" will evolve "H_(2)=(22.4)/(98)xx26=5.94L`