২ লিটার ০.২ মোলার সোডিয়াম কার্বনেট দ্রবণে কি পরিমাণ সোডিয়াম কার্বনেট আছে?
To solve this problem, let's analyze it step-by-step:

Step-1: Identifying Concentration and Volume-
Concentration of the Sodium Carbonate solution (Na2CO3) = 0.2 M (decimolar)
Volume of the solution = 2 L

Step-2: Calculating Moles of Na2CO3-
Since concentration (C) is defined as moles of solute per liter of solution (C = moles/L), we can directly calculate the number of moles of Na2CO3 in the solution:
moles of Na2CO3 = C * V = (0.2 mol/L) * (2 L) = 0.2 mol

Step-3: Determining Molar Mass of Na2CO3-
Here, atomic mass of Sodium (Na) is 22.99 ≈ 23, mass of Carbon (C) is 12, mass of Oxygen (O) is 16.
The molar mass of Na2CO3 (M) is (23*2+12+16*3) = 106.0 g/mol, which represents the mass of one mole of sodium carbonate.

Step-4: Calculating Mass of Na2CO3-
Finally, we can determine the mass (m) of Na2CO3 in the solution using the following formula:
mass of Na2CO3 (m) = moles of Na2CO3 (n) * molar mass (M)
m = (0.4 mol) * (106.0 g/mol) = 42.40 grams

#Answer: 42.40 grams
