The correct answer is option B. X-rays are the waves found in the electromagnetic spectrum at a wavelength of 1x10^-11 - 1x10^-8 m and frequencies of 3x10^16 to 3x10^19 Hz. These waves penetrate easily through certain materials which made them usefule in the field of medicine.
First, we shall calculate the total number of moles present in the final solution.
Number of moles in 0.50 m NaCl = molarity * volume = 0.50 * 3.0 = 1.5 moles.
Number of moles in 0.2777m NaCl = molarity * volume = 0.2777 * 9.0 = 0.24993 moles
Total number of moles = 1.5 + 0.24993 = 1.74993 moles
Second, we shall calculate the total volume of the final solution.
Total volume = 3 + 9 = 12 litres.
The molarity = total number of moles / total volume = 1.74993 / 12 = 0.1458 m
