Question

How many moles of sodium chloride are there in 250 ml of a 1.20 m solution of nacl? 1. none of these 2. 0.60 3. 1.2 4. 2.4 5. 0.30 6. 4.8?

Answer 1

Molarity is defined as number of moles of solute in 1 L solution
molarity of the NaCl solution is 1.20 M
in 1 L NaCl solution there are 1.20 mol
therefore in 250 mL solution there are - 1.20 mol/L x 0.250 L = 0.30 mol
there are 0.3 mol of NaCl in 250 mL 
the answer is 5) 0.3 mol