Active mass of 5.6 lit  N₂ at STP

Explanation

At STP (Standard Temperature and Pressure), 1 mole of any gas occupies 22.4 L.

Number of moles (n) = Volume of gas at STP / Molar volume at STP

n = 5.6 L / 22.4 L/mol

n = 0.25 mol

Active Mass = Number of moles / Volume (L)

Active Mass = 0.25 M

Since 0.25 is equivalent to 1/4 and can also be represented as 1/22.4 M when expressed as active mass in STP conditions.

Thus, the correct answer is: Option (c)

Final Answer:

Option (c): 1/22.4 M