The number of molecules and moles in \( 2.8375 \) litres of \( \mathrm{O_2} \) at STP are respectively:
\( 7.527 \times 10^{23} \) and \( 0.125 \, \text{mol} \)
\( 7.527 \times 10^{22} \) and \( 0.125 \, \text{mol} \)
\( 7.527 \times 10^{22} \) and \( 0.250 \, \text{mol} \)
\( 1.505 \times 10^{23} \) and \( 0.250 \, \text{mol} \)