An aqueous solution of NaCl is 270m. If the density of the solution is 1.20g/ml. Find a) % NaCl by mass b) Molarity of NaCl in the solution.

I assume you men 270 molal.

270 m means 270 mol/kg solvent.
g NaCl = 270 x 58.5 (apprx) = estimated 16000 g (you need to go through the entire problem and redo the math; I've estimated all of these numbers.
The mass of the solution is 1000 g solvent + 16000 g NaCl = about 17000g total
%NaCl = (mass NaCl/total mass)*100 = about 94%. I'll wait to do the b part until you've confirmed this post is correct.

To find the answers to the given questions, we'll need to use the formulas for percent by mass and molarity.

a) Percent NaCl by mass:

Percent by mass = (mass of solute / mass of solution) x 100%

To calculate the mass of solute (NaCl), we'll multiply the volume of the solution by its density:

mass of solution = volume of solution x density

mass of solution = 270 ml x 1.20 g/ml

Now, to find the mass of NaCl, we'll use the density of water (since NaCl is dissolved in water).

1 ml of water has a mass of 1 gram. Hence, the mass of water in the solution is:

mass of water = volume of solution (in ml) x density of water (1 g/ml)

mass of water = 270 ml x 1 g/ml

Now, we subtract the mass of water from the mass of the solution to find the mass of NaCl:

mass of NaCl = mass of solution - mass of water

Now, we can calculate the percent NaCl by mass:

% NaCl by mass = (mass of NaCl / mass of solution) x 100%

b) Molarity of NaCl in the solution:

Molarity (M) = moles of solute / liters of solution

To calculate the molarity, we need to find the moles of NaCl. First, we need to calculate the mass of NaCl in grams, using the same formula as above (mass of NaCl = mass of solution - mass of water).

Then, we can convert the mass of NaCl to moles using its molar mass. The molar mass of NaCl is 58.44 g/mol.

moles of NaCl = mass of NaCl / molar mass of NaCl

Finally, we need to determine the volume of the solution in liters. We convert the given volume (in ml) to liters by dividing by 1000:

volume of solution (in liters) = volume of solution (in ml) / 1000

Now, we can calculate the molarity:

Molarity (M) = moles of NaCl / volume of solution (in liters)