Plants in a garden make use of 22.4 liters of carbon dioxide at S T P (Standard temperature and Pressure) The number of molecules of carbon dioxide utilized by the plants is,

According to Avogadro’s law, equal volumes of all gases contain an equal number of molecules at a constant temperature and pressure.

The standard molar volume of a gas is the volume occupied by one mole of any gas at 273 K and 1 atm pressure (STP). It is 22.4 litres. It is the same for all gases. And we know that 6.023×10²³ molecules are present in one mole of any gas. So the number of molecules of carbon dioxide utilized by the plants will be 6.023×10²³.