Solutions A, B, C and D are respectively 0.1 M glucose, 0.05 M NaCl, 0.05 M BaCl2 and 0.1 M AlCl3. Which one of the following pairs is isotonic?

Isotonic solutions have same molar concentration of solute particles in solution. Molar concentration of solute particles in solution are 0.1 M in glucose, 2 x 0.05 M in NaCl, 3 x 0.05 in BaCl2 and 4 x 0.1 in AlCl3. Therefore, 0.1 M glucose and 0.05 M NaCl solutions are isotonic.∵π=iCRT , where C= concentration in Molarity