Question

The number of moles present in 11.2 litres of ${\text{CO}}_2$ at S.T.P is:

• A. 0.5 mol
• B. 2.0 mol
• C. 2.5 mol
• D. 0.2 mol

Answer 1

The correct option is A

0.5 mol

Given volume of carbon-dioxide $\left({\text{CO}}_2\right)$ at STP = 11.2 L
Molar volume at STP (in litres) = 22.4 L
In case of gases at STP,
Number of moles = $\frac{\text{Volume at STP (litres)}}{\text{Molar volume at STP (litres)}}$ .... (i)
Inserting the values of the volume of carbon-dioxide at STP and molar volume at STP (litres) in equation (i) we have:
Number of moles = $\frac{11.2}{22.4}$
$\therefore$ Moles present in 11.2 litres of ${\text{CO}}_2$ at S.T.P is 0.5 mol.