Question

4. (10 points) What molarity of HCl stock solution is needed so that 2.5mL of this stock solution diluted to 0.15L will yield 25mM?

Answer 1

i] we prepare 25 mm = 0.025 m, 0.15 lit (150 ml) from 2.5 ml stock soln. dilute to 150 ml. ii] So, molarity of stock soln. is iii] N_1 V_1 = N_2 V_2 N = Normality V = volume M_1 V_1 = M_2 V_2 M = Molarity V = volume iv) M_1 V_1 = M_2 V_2 M_1 = Molarity of stock soln. volume of stock soln. = V_1 = 2.5 ml of stock soln. Molarity of prepare soln = M_2 = 25 mm = 0.025 M volume of prepared soln = V_2 = 0.15 lit = 150 ml. v] M_1 times 2.5 = 0.025 times 150 vi] M_1 = 0.025 times 150/2.5 = 1.5 M vii] The molarity of HCl stock soln. is 1.5 M viii] In nM: 1500 nM stock soln. of HCl