Question

Volume of $CO_{2}$ obtained from complete decomposition of $20 \,g$ $CaCO_{3}$ at STP is:

• A. 2.24 litre
• B. 4.48 litre
• C. 20 litre
• D. 22.4 litre

Answer 1

Answer: (B)

4.48 litre

Answer 2

$\underset{\overset{(40 +12 +3 \times 16)}{=100}}{CaCO _{3}} {->[\Delta]} CaO +\underset{22.4\, litre}{ CO _{2}}$
$\because 100\, g\, CaCO _{3}$, on decomposition, gives
$=22.4$ litre $CO _{2}$ at STP
$\therefore 20\, g\, CaC 0_{3}$, on decomposition, will give
$=\frac{22.4 \times 20}{100}$
$=4.48$ litre $CO _{2}$ at STP