I think it’s D.
sorry if it’s wrong
(C) 0.1 mole of NaCl dissolved in 1,000. mL of water
<u>Explanation:</u>
The conductivity of 0.1 mole of NaCl dissolved in 1000 mL of water will be greatest as the number of ions in 0.1 mole of NaCl will be more than 0.001, 0.05 and 0.005 moles of NaCl. Greater the number of ions in the solution, greater will be the conductivity. Specific Conductivity decreases with a decrease in concentration. Since the number of ions per unit volume that carry current in a solution decrease on dilution. Hence, concentration and conductivity are directly proportional to each other.
I can give you a clue of getting mass. if it is the atomic number is even multiply by 2 but if the atomic number is odd multiply by 2 and add 1
sodium atomic number = 11 so mass = 11*2 +1 = 23
oxygen. atomic number = 8 so mass = 8*2 = 16
carbon atomic number = 6 so mass = 6*2 = 12