in this qustion 2400 where it is come from

You meant 22400?**22.4 l** of a gas refers to the volume of 1 mole ( molecules) of a gas at **STP** (i.e. Standard Temperature and Pressure) which is 76 mm of Hg pressure and 273 K temperature. **22.4 l** is also called the molar volume of a gas. (*Google*)

Since everything is in ml, therefore 22400ml is used.

You meant 22400?**22.4 l** of a gas refers to the volume of 1 mole ( molecules) of a gas at **STP** (i.e. Standard Temperature and Pressure) which is 76 mm of Hg pressure and 273 K temperature. **22.4 l** is also called the molar volume of a gas. (*Google*)

Since everything is in ml, therefore 22400ml is used.