Question

The reaction of calcium with water is represented by the equation $Ca + 2H_2O \rightarrow Ca(OH)_2 + H_2$ What volume of $H_2$, at STP would be liberated when 8 g of calcium completely reacts with water

• A. 4480 $cm^3$
• B. 2240 $cm^3$
• C. 1120 $cm^3$
• D. 0.4 $cm^3$

Answer 1

Answer: (A)

$\underset{\text{40}}{Ca}+2H_{2}O \to Ca(OH)_{2}$+ $\underset{\text{$22400\, cm^{3}$}}{H_{2}}$
$8 \,g$ of calcium will produce $=\frac{22400 \times 8}{40}$
$=4480\,cm^{3}$