JEE Main · 2023 · 31 Jan 2023 · Shift 1 · Some Basic Concepts of Chemistry

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Zinc reacts with hydrochloric acid to give hydrogen and zinc chloride. The volume of hydrogen gas produced at STP from the reaction of 11.5 g of zinc with excess HCl is ______ L (Nearest integer)
(Given : Molar mass of Zn is

65.4 g mol^{- 1}

and Molar volume of

H_{2}

STP = 22.7 L

)

Answer: 4

Solution

The reaction

Zn + 2 HCl ZnCl X_{2} + H X_{2}

gives one mole of hydrogen per mole of zinc. The amount of zinc is

\frac{11.5}{65.4} = 0.176 mol

, so

0.176 mol

of hydrogen is produced. At STP its volume is

0.176 \times 22.7 = 3.99 L

, which to the nearest integer is

4 L

JEE Main · 2023 · 31 Jan 2023 · Shift 1 · Integer answer

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